I went ahead and purchased one the other week. It's a great little device and i'm happy I got it. It reads in all my ePubs both from google and non-DRM sources. It does load up on my mac just fine and i can use it with caliber. Unfortunately, I'm having the issue that others have with not being able to read DRM-ePubs from other sources.
I'm downloading the iRiver story 1.0 firmware but I wonder if that'll fix issues or if the Story HD just won't read ePubs from Booksamillion or Sony themselves.
Anyone have any other suggestions?