I just switched to Android (Motorola Droid) after several years of using uBook on the Win Mobile platform. That powerful e-reader can view virtually any format you throw at it, is full-featured, and highly configurable. But it's anything but pretty. So with that experience in mind, I tried to find an Android e-book reader which had similar features. The three which seemed most widely-used are: FB Reader 0.5.27 (FBReader: FBReader for Google Android) Aldiko 1.2.5 (Aldiko - eBook Reader Application for Android) Books WordPlayer 11.0.1 (WordPlayer:Reading Released) Each of them open epub files, but only FB Reader would open any other formats (oeb and fb2). However, thanks to the genuis of calibre (calibre - E-book management) a free e-book management and conversion application which can convert between almost any format invented, having a reader which can read a specific format is less important - simply use calibre to convert it to epub. Each of the readers has the following features: -- Configurable fonts (color/style/size) -- One button toggle for day/night mode -- Bookmarks None of them has annotations/highlighting, which is the feature I miss the most from uBook (Word-Player apparently does, per its home page, but per the devs, that feature is not working in Droid). FB Reader This is the oldest of the ebook readers, with versions available for multiple platforms. It is also butt-ugly, with an interface that makes my trusty uBook seem spiffy by comparison. (e.g. you have to select books from a list, not icons). And the cover displays in only 1/3 of the screen, in the top left corner (presumably FB Reader is not yet designed for the hi-resolution Droid). FB Reader was also the buggiest of the three readers. It crashed frequently when trying to change font size, only curable by rebooting the phone, and froze up randomly. Also the Table of Contents was faulty - it would only show one chapter. Another quirk - the menu system appears to be in flux - the font settings was buried in a menu called "Settings (Old)". Two pluses - (1) the FB Reader's bookmarks feature was the easiest to use of three. Selecting "Bookmarks" brought up one screen at which you could both see a list of recent bookmarks, and add one with one-touch. But the ease of use comes with the loss of flexibility - the bookmark is named after the first few lines of the page, w/o the ability to override it, and (2) it has the option to show/hide the status bar while reading. WordPlayer This one seemed promising at first, if only because it interfaced with calibre directly. It was also the only ereader to have text-to-speech, but with a voice that not even a mother could love that also read formatting, it was too distracting to use. One other plus - you could point it to any folder on your SD card to find an book, and it would import it. This reader was the slowest of the three - chapters took forever to load, and switching between day/night modes was just as painfully slow, as if the entire chapter had to be reloaded. A couple of other quirks/bugs - a single italiziced letter would often not display, and it added several white blank pages to the end of each chapter. Aldiko This is certainly the prettiest of the three ebook readers. It also has agreements with various download sites to enable downloading of something like 10,000 ebooks, but the selection was poor, seeming to consist primarily of sex stories (or erotica). However, since I simply use the reader to view my own epubs, this feature didn't matter to me. And it also was easy to download epubs from the web - clicking on an epub file would import it into Aldiko. This was my favorite of the ebook readers - the devs put a lot of thought into the interface and usability, and I found no bugs. Chapters loaded quickly, it was the only reader which supported css (though not the @font-face attribute), has fully-configurable gestures, and even an option to brighten/dim the screen by swiping the screen w/o leaving the page you're on. The bookshelf has to be seen to be believed - beautiful icons, intuitive, and the ability to sort by author, tag. Finally, you can share books via facebook, twitter, e-mail, or even SMS(?). This would be the ideal ebook reader, and a great replacement for uBook if only it had annotations & highlighting (dev says "we will definitely add in the near future", though there have been two updates in the month since then, and still no dice). And I miss the customized status bar that uBook has, with page number / total pages, and the time.