The Verge has a review of the HTC One on AT&T, and the phone is packed with bloatware from the carrier.
The most annoying piece of bloatware, however, is AT&T’s Address Book, which attempts to take over the contacts application in an effort to sync it with the carrier’s own cloud service. Not only is it annoying, but its nags are persistent — even if you’ve dismissed it once to tell it that you don’t want to use it, it will come back at a later date to remind you again of its existence. Oh, and this particular carrier app can’t be disabled or uninstalled.
I’ll keep my iPhone, thank you.