My dad had AT&T uverse and had all kinds of problems with download speeds. Speed tests were O.K. but even SD videos from youtube or whatever would stutter like crazy. He'd have to pause it to let it load for a minute or two before being able to play it smoothly.
Pingplotter showed various points of lost packets in AT&T's networks and I fought with their support for quite a while which yielded no results. He actually had to make me give up the fight because he didn't want to "stir the pot".
Recently he switched to Charter internet and has had flawless internet ever since.
I live only 20 miles away and use AT&T uverse with no issues whatsoever. I'm not necessarily happy with my download speeds but that is due to my being cheap.. I'm getting the speeds I'm supposed to get so I can't complain. I get no dropped packets and almost never lose connection with Aces High.
For whatever reason I get routed through different paths than my dad used to.. maybe it's because I also get TV service through uverse.. or it may be due to physical location. Who knows?
You can fight with their customer support for hours and have a small chance of it getting pushed up.. but more than likely you'll just be wasting your time. You'll have much better luck signing up for a free dslreports.com account and posting your problems in their
direct support forums. Techs from various ISPs hang out there and can get you service that you wouldn't be able to get over the phone.