I'm not sure if I should even bother responding to you or not. I apologize in advance if I have a bad impression of you, but so far you are coming across to me as a Sprint fanboy who has no idea what he is talking about- only ranting about Sprint being the best in every imaginable way, with no facts to back it up.
As for your ATT question- yes, of course I have heard of them. I have even had several AT&T phones over the years (up until October, when I left AT&T for Sprint because their Touch Pro 2 was released while AT&T was dragging it's feet, and Sprint's plans were cheaper- especially with AT&T's new data plan requirements). And I can tell you right now, their 3G is WAY better than Sprint's (at least where I was using it). Here is an independent test done on all of the big carriers' 3G in the USA:
AT&T Roars Back in PCWorld?s Second 3G Wireless Performance Test - PCWorld
Notice AT&T sitting at the top?
Notice they don't test T-Mobile's HSPA+ or Sprint's Wimax because it wouldn't be fair to the 3G on Verizon and AT&T. So out of the 3G options, AT&T was the best.
They DID test T-Mobile's HSPA+ and Sprint's Wimax here though:
WiMAX vs. HSPA+: The Hands-On Test - WiMAX vs. HSPA+ Roundup | PCMag.com
Notice T-Mobile's HSPA+ came out on top.
Please, get your research done before you post that kind of stuff.
I am not a Sprint hater, by the way. I have Sprint right now, and have used Sprint off and on for many years. I follow the best phones. Whoever has the best phone, I go with them. If 2 carriers have a phone I want, then I look for the cheaper option with that phone. I have no loyalty to any carrier, and the only company you could say I was a fanboy of is HTC (as most of the best phones over the years, to me, always seem to be made by HTC). I have used many carriers over the years and my opinions come from not only lots of experience, but also research and proven facts. It's not just some fanboy rant trying to convince everyone that my favorite carrier is the best. And I would hope that if you engage in discussion that compares carriers, you would also leave the fanboy rants at the door.