The caps wouldn't be that bad if the service didn't *utterly* suck.
The gateway they give you is the only thing that works with the service (you can't use your own hardware, or at least nobody has found a way to). It won't do any kind of bridge mode. It won't talk to more than one IP per MAC address, so you can't put a router behind it (unless that router is doing NAT for *everything*). It randomly drops connections, especially long lived ones -- I can't make local backups of my server in a remote datacenter anymore, because the connection will almost never stay alive long enough to transfer the whole ~400MB. Sometimes it starts blocking random incoming connections, even to static, un-natted, unfirewalled addresses -- one day I can't get to my webserver from the outside world for a few hours... the next I can't ssh into my home server ("unknown inbound session stopped" ... of course it's unknown, it's the first packet of a new connection, you piece of garbage). It supports logging to syslog, but outputs a constant stream of useless messages so thick that it's almost useless.
Recently I've started to notice having periodic problems downloading content (like the slashdot style sheet!) from akamai-based sites, which a little bit of goggling shows to be an ongoing U-Verse problem since 2008.
The support sucks massively. If you call with basically any problem beyond "my internet is down" they will forward you on to their "advanced" support department, who has a fee of $39 (might be $29... don't remember)... which they'll charge you even if all they do is tell you that they can't help you and you need to call regular support.
Netflix, on my 24Mbit downlink, varies from "great quality" to "OMG you can barely do SD quality"... many other people report this as well. Some days the performance is great, some days the performance is just absolutely miserable. I'd try to see if there was some common network path causing problems, but they basically disable traceroute for all of their internal nodes (I'm guessing they just stop them from sending TTL exceeded datagrams completely).
You can't switch back to ADSL -- they wouldn't even let me get U-Verse service unless they disconnected my ADSL at the same time. But it is "no longer available" so now I'm stuck with this garbage.
I'd gladly take a usage cap if it meant any of this crap would get better. I'm somehow doubting it, since not a bit of it seems like it's related to network saturation... just lousy service. And my only other choice in this area (AFAIK) is Comcast, who also has caps, along with their own set of problems...
I'd say "welcome back to the 90s" ... but my network worked a lot better back then. So I guess... welcome to the future!