I just bought one and I am very impressed with it. I can't wait to see what OS 2.0 will bring us in February.
The Kobo app works just the same as it does in Android and on the PC. The stand-alone-reader allows side loading as well as sdhc card access but the app restricts you to store and account/library access only.
With the advent of porting Android apps over to the PB it should enhance it's use dramatically.