I have a TM tab,
I use the kindle and it is pretty straight forward. It syncs perfectly with my pc, itouch. I can even download my own mobi files via usb. Only thing is cover of books don't come over.
I also have a nook app and a book reader app, aldiko. I can tell you the Nook app did download my books I purchased thru the B & N reader, but the same issues are happening that made me stop using it on my itouch, the screen freezes. I like the page turning on the nook. Also with this one, I can upload epub books via usb, and covers don't come over. I am still holding out on the nook, I will give it another few trys, if not I will delete the app..
I love and use the aldiko reader. It has a bookshelve similiar to the ipad reader, I can upload my epub via usb, the cover images come over. there is a dictionary but you have to type in the word and it will search via web.
one of the reasons i wanted the tab was for ereading, I have a kindle but missed having a backlight and seeing the color images of the cover.
hope this helps. if I can answer some more q's just let me know.