Yesterday was my first day with a PRS-300. It couldn't be easier to use. Easier than my son's ipod, if you ask me.
Using the Sony bookstore was a breeze. Authorize the reader in account settings, add a book to your shopping cart, and buy. The download happens automatically.
If you just want to copy your whole library to your reader, there is a big "sync" button. In Sony's library software, click the reader on the left, then the big "sync"button. Everything in your library will copy over.
As a first ereader, I couldn't be happier. Easy to use, easy to sync, and very sharp display. I say go for it. For $199, and a 30 day return policy, what's to lose?