If you have an Android device - either a smart phone or a tablet computer or a Nook Color running CM7 - then you've probably noticed you have a lot of choices when it comes to what reader application to use. There's the store apps, of course: Amazon Kindle, B&N Nook, Sony Reader (although that one is only available on the Google Market for the most recent Android builds, so I haven't been able to try it out), and Kobo. And then there are the third-party apps: Aldiko, Moon+, Cool Reader, and many others.
So which reader app is the best one? Well, that's going to depend a lot on individual preference, but a major factor lies in how you read. One of the things I really like to do when reading is make a lot of highlights and notes - and I need to be able to export those notes quickly and easily to some kind of text file. For my money, the Moon+ reader app is the best app out there for highlights and notes.
Moon+ was something of a trend setter in that it was the first app I could find that really embraced the concept of highlighting slider bars. Where other apps force you to try to guess where to stop moving your finger and hope that everything you want highlighted has been selected, Moon+ has intuitive slider bars that hang well below the text and are easy to position (and reposition) exactly where you want. Though the Nook and Kobo apps have recently (as of last month) added highlighting sliders bars, the Moon+ implementation continues to be easier to use in my opinion - the Kobo app takes you into a special "instance" of the page for highlight which means long loading times per highlight, and the Nook "magnifying bar" forces you to move your finger while your eye watches via a little overhead rear view mirror.
Besides the incredible 4-set-colors-plus-any-custom-color-you-want highlighting functionality, Moon+ also provides a valuable note taking interface. If you want to place a note during reading, it's very easy to highlight the selection, tap "note", and write in whatever thought you wanted to link to that passage. The notes even hover over the reading area, so you can see them while flipping through the book.
Ultimately, though, notes and highlights are only as useful as the method via which you can extract them. You can take all the notes in the world on a device, but if that device crashes and loses data, you'll have lost all those notes if there's no means to export and back them up regularly. This is why I love Moon+: you can go into the "bookmarks" menu at any time and easily "share" your notes and highlights out to a variety of sources.
I used to email my notes to myself, but now that Evernote integration has been added if the Evernote app is installed, it's just as easy to export all my notes and highlights to an Evernote, and then I can access those notes at any time, anywhere. It's quite delightful.
The Moon+ system isn't perfect - the exported highlights do contain the entire text of the highlight, but they don't make a note of the source page or the color used to make the highlight, which means that any personal "differentiate highlight types by color" system will run into problems on a highlight export, but at the same time it does so many things right that it's hard to hate too much on the app.
Beyond being the only reading app I can find that provides highlight/note export, it is also one of the few that will let you map display brightness to a left side up/down swipe and text size to a right size up/down swipe, and it's amazing to me how intuitive that mapping is. Plus, Moon+ supports 3G/WiFi cloud library retrieval, which already makes it one of the best readers on the market. Bottom line: if you like to read on your Android device and you love to annotate your books, Moon+ is well worth a try.