there isnt much to compare the AT-T rom is full of AT-T apps that just take up space and are a pain to deal with unless you pay the monthly fee to use them. Its the same Base rom just AT-T fills it with BS crap. I would use the HTC shipped rom which i do since it has the today screen(the one you are talking about) and have much less junk in it. Problem is is the Kaiser is not CID_unlocked yet so we can't change roms from AT-T to HTC or vice vera. PLease do some reading before you ask questions I was nice since this is your first post!
Back to XDA where it all started over 10 years ago back in the "Hermes" days on windows mobile 5 things have come a very long way in portable devices
Now rocking a Samsung Galaxy S II (I777)
With Custom Built ROM with a little mix of all the best!