MobileMe to iCloud - Still have two Apple accounts...

So, finally was able to get MobileMe merged over, however on my iPhone 4, I still have MobileMe and iCloud logged into iCloud (mobile me says it's iCloud now). I was under the impression that this would merge the two disparate accounts (the Apple Store/Forums account vs. Mobile Me) into one, but apparently it doesnt. Also, now that I have successfully logged into iCloud on this device it wants to 'merge' my bookmarks (which were synced via MobileMe) on the phone to the iCloud. Is it smart enough not to duplicate? I've had several personal horror stories (although I've backed up everything) with iTools/MM/etc., over the years, so I'm curious.

Anyway, any ideas or something assuage my concern?