I'm probably one of the minority, but I've never used Caliber and I've never had a problem with the Sony bookstore. I had some trouble with the Sony Library when I first got my 700 almost two years ago, with syncing and creating collections, but I don't use the sync feature anymore. It's not perfect (the Library software), but I'm not a perfectionist and have lived with its quirks just fine.
P.S. Don't forget to change your profile to update your "device" from none to your 650!