The Ibis reader was released a week ago and it gets a very solid review from the Wired blog Gadget Lab:

Ibis reader is an e-book reading application that does everything that you’d expect an iPhone e-reader to do, with one big difference: It doesn’t come from the App Store. The app runs on any iPhone or iPod Touch and offers full offline access to your library of books, and is as fast and responsive as a native iPhone application. It manages this through the magic of HTML5, which is supported by Mobile Safari and – crucially – offers offline storage for web-sites. (Ibis reader for iPhone a web app that thinks its a native app)

It also runs on Android, of course it should — it is a web app, though I have not checked this out myself. At Exact Editions we dont care too much about eBooks and the ePub standard. We think digital editions are much more important. But we like the style of the Ibis reader, and we definitely think that eBooks should be done well if they are done at all. Doing them well should encompass, doing them in such a way that users do not get locked down into a proprietary standard, nor is it good if publications are made available only through a sole e-commerce solution (whether Kindle, or iTunes or something else). There has to be consumer choice; and Ibis is also an elegant piece of software development which works nicely on my iPhone and on the desktop. All round it is to be applauded.