• Apple’s iBooks
• Amazon Kindle for iPad
• Barnes and Noble eReader
• Kobo Reader (which is also the Borders eReader and will soon be the Whitcoulls eReader for the iPad)
• Ibis Reader (this is interesting because it’s actually an HTML5 web app rather than a native iPad/iPhone app)
• Stanza
• vBookz (actually a text-to-speech reader app rather than a traditional e-reading app)

Among Perlow’s findings:

• Apple’s iBooks is the flashiest but “of all the reader applications we’ve looked at, it is actually the least functional. Apple designed iBooks to behave and act like a real book, and focused more on the aesthetics and UI than actual App functionality with the initial release.”
• Amazon’s Kindle wins in terms of the size of its 600,000-title ebook store but “from a feature perspective, the Kindle software is pretty weak when compared to its hardware counterpart.”
• Interestingly, it’s the Barnes and Noble eReader that wins the highest plaudits from Perlow. “Of all the paid content readers, by far the best one in existence is probably the Barnes & Noble eReader application.” But it’s probably not so useful outside of the US because of its ties to the very US-focused B&N store.
• Of particular interest in this part of the world is the Kobo which will shortly be released in this part of the world as the Whitcoulls reader app. For Perlow, it stacks up pretty well. “It’s extremely polished and very well-designed,” he says.
• The Ibis Reader is different from the others in being written in HTML5. It reads non-DRM ePub files. “Compared to the other reader apps on this list, the reading features within Ibis Reader are pretty spartan. … However, the interface is very clean and simple to use, and the reading experience is actually pretty good when compared to the native apps.”
• Stanza was the original e-reading app that popularised e-reading on the iPhone. It’s the latest to the iPad party but the result is good according to Perlow. “Stanza is by far the most sophisticated e-Reader application for iPad, as it supports not only the open EPUB format but also the legacy Mobipocket, PalmDoc (DOC), Microsoft LIT formats as well as HTML, PDF, Microsoft Word and Rich Text Format (RTF)…. If you have lots of content that you’ve collected over the years, Stanza is definitely a must-have app. There’s absolutely no downside, it’s free to use and does more than any e-book reader app on this list.”
• vBookz is a US$2.99 text-to-speech reader which works only with public domain ebooks  at this stage. Perlow concludes, “vBookz is an extremely interesting and exploitative iPad application, and one which may be good for getting children interested in classic literature and also a useful app for the visually impaired.”

Read the full ZDNet e-reader app review here.

UPDATE: ZDNet has also posted a comparison of ebook reader apps for the Google Android platform. Check it out.

The reason is an escalation in Apple’s long-running battle with Adobe over its Flash platform. Apple’s latest move bans any content generated using Adobe’s Flash software from its App Store. Flash is one of the most commonly-used systems for creating rich, interactive content.

This might seem like an esoteric spat between two tech Titans but the latest turn in this long-running dispute will be a special blow to magazine and newspaper publishers, and to book publishers who were hoping the iPad would open up textbooks and illustrated books unsuited to the more basic Amazon Kindle-style ebook readers. Ironically, this ban looks like it might catch out some of the high profile magazines and newspapers, such as Wired and the New York Times, that have been trotted out in the past few weeks to show off the iPad’s capabilities.

Publishers (and indeed other media companies such as video and game developers) are heavily invested in Adobe’s applications for creating their content. They don’t want to learn new tools, they want their existing tools to take them into the new media.

[Update: 5 May 2010. Apple's move may prompt an anti-trust probe, according to this New York Post story. ]

So Adobe’s strategy with its Flash platform — to make rich media content available on any platform without having to produce a different edition for every device out there — promised to take a big burden off publishers and open up their content to the whole market.

Until Apple came along with the iPhone and now the iPad.

Apple refused to host Flash on these devices. Now that these devices are ruling the mobile web roost, their Flash no-show leaves a big hole in this tidy strategy, moving this spat from an irritation to a serious business problem for content developers.

Recently it appeared that Adobe had found a clever work-around to circumvent Apple’s strictures using technology called Packager for iPhone. This turns Adobe’s Flash code  into the native program code used by Apple’s iPhone and iPad. It’s set to be released this week with the latest CS5 update to Adobe’s software.

Apple, however, used the launch a couple of days ago of OS4.0 — a major upgrade to its operating system for iPhones, iPads and iPod Touches — to introduce new contractual terms to its tightly-run developer programme. The new terms have the effect of stymieing Adobe’s work-around and look likely to keep all Flash applications off the Apple devices permanently.

In doing so, Apple hopes to force publishers and developers to create native applications written especially for its devices instead of using Adobe’s system to produce a single generic edition to run on many different devices such as an iPad, a Blackberry and a Google Android device.

Apple hopes its move will cause publishers to rethink their strategies. Forcing publishers to produce multiple editions, or to drop support for less important platforms is great for Apple but bad news for publishers and will also lessen the chances of competing devices succeeding against Apple.

It should certainly cause publishers to rethink their strategies but not in the way that Apple hopes.

Fortunately, there are things publishers can do. But it means they’ll have to show some restraint in the face of all the “flashy” new toys for producing great-looking content, and the smooth payment system that Apple is throwing in their direction.

While Apple is exercising an iron grip on its App Store, it’s still open to the web. So developers and publishers can sidestep the App store’s strictures and use standard web technologies – including HTML, CSS, and Javascript – to produce rich, interactive content that will run on the iPad, iPhone or the many other devices that offer web access.

Ironically, this is made easier by Apple’s solid support for web standards and, in particular the emerging HTML 5 specification. Many useful HTML 5 features are already widely implemented, including the ability to run offline web apps so you don’t have to be connected all the time. Others, such as native support for video and audio (no external plug-in programs required), are not far behind. The Safari browser and open source Webkit framework that Apple uses in its iPhone and iPad are, so far, being good corporate citizens in their support of these important emerging standards.

In this regard, a useful development framework is Phonegap. This system allows you essentially to turn a website built using HTML, CSS and Javascript into an iPhone app. And according to its developers, their system, while superficially in the same boat as Adobe’s Flash platform, will survive Apple’s change to its developer terms. It offers a path to Apple’s iPhone App store as well as the Google Android app marketplace and the Blackberry.

For publishers, the downside of this is that the toolset is more the domain of web developers than their graphic designers. But they’re going to need to upgrade web capabilities anyway and sticking to web standards will make a reasonable fist of cross-platform rich content.

This is especially true for book publishers who already have a widely adopted ebook standard called ePub which is based on (X)HTML and CSS web standards (and is the standard adopted by Apple in its new iBookStore). Newspaper and magazine publishers have yet to rally behind a standard but it’s almost certain to be based, again, on web standards.

If the publishing industry can get its act together quickly enough, it’s quite possible that all of the print media could use the same standard. For instance, work on the next version of ePub should have better support for interactivity, rich media and the more story-centric structure that newspaper and magazine publishers need.

In the short term, this approach won’t offer the same slickness as a hardware-specific iPad edition, but it still offers a credible way to produce mobile media that will work for readers and advertisers. And it — or its threat — might just help nudge Apple off its path to world domination of the media business.

The big event while I was absent was the Consumer Electronics Show in Las Vegas last week and it delivered on its promise that eReaders and tablet devices would be the buzz at this year’s CES.

This New York Times story covers the deluge of devices announced for reading a surfing.

And this round-up story from E-Paper Central covers the main e-paper based ebook reader announcements well.

For the most part, it will be a few months before we’ll see availability of the new devices, and perhaps longer in international markets, especially if these devices take off with consumers and product shortages slow the international roll-outs. But it’s clear that consumers wanting to read ebooks are going to have plenty of choice.

But a couple of the big announcements happened outside of CES. Google got into the Android smartphone business with the launch of its Nexus One. And the already-overheated rumour mill about Apple’s forthcoming tablet device has gone into top gear with a plethora of stories appearing now that are picking a late January announcement and March ship date for what’s being billed as the iTablet or iSlate. The amount of coverage and detail now emerging makes this look increasingly likely. Another game-changing battle emerging, anyone?