Until very recently (a little over a week) I have been using FBReader on my HTC EVO 4G and Mobi Reader on my PC and Asus tablet/convertable, Using DarkReversaer and Calibre to give me DRM free compatible files for each. I ran across a book that I couldn’t find in Mobi format, so I decided to buy the Kindle version and since I had Kindle readers on ALL of my devices I just used that.
In spite of the fact that the Kindle readers are relatively featureless, I discovered that WhisperSync more than made up for two page display, swipe to change page, et. al. missing features. Since I frequently jump from device to device to read depending on my circumstances, having them automatically synced rather than doing clumsy word searches to sync them is WONDERFUL.
I don’t mind the DarkReverser/Calible/USB flail to load books, but the sync feature alone is worth it. And one click/Whispernet downloads is just icing.