Did you just offer up posts on you tube for pic quality?
And you think AT&T gets all the way up to 6?
Measured at the U-verse gateway, AT&T's HD streams for video are approx. 5.7 Mbps. This makes sense as on the 32/5 U-verse profile (this is the one assigned to you on AT&T's fastest Internet speed offering, 24/3 Mbps) - one's Internet connection speed drops to 20 Mbps when viewing two HD channels at once - 14 Mbps when viewing 3 HD channels - and just 8 Mbps when viewing four HD channels. So yes, Internet speed loss on U-verse when viewing 2 or more HD channels definitely correlates with the 6 Mbps of bandwidth per HD channel as well.
The point of the comparison was to illustrate how bad AT&T U-verse looks at that bitrate - that a recording from Verizon FiOS of the same channel uploaded to YouTube
still looks better than AT&T even after
YouTube molests it. It's that
As for whether or not DirecTV looks any worse with the 25% bitrate drop, I'd take opinions without some screenshots to back it up with a grain of salt. In the other thread about DirecTV HD channels the majority opinion is that the new channel they're adding, TCM HD - "looks great." This is despite the fact that it is the only high definition channel that has never aired a single minute of native high definition content. Most people are clueless when it comes to picture quality.
Really the only way to know scientifically is for a thorough identical frame screenshot comparison to be done like the AT&T vs. YouTube comparison above: screenshots need to be taken of a program before it gets dropped down to 6 Mbps and then a repeat of the program after the channel is dropped down.