Terrible signal...
First off, let me say I love this phone. Well designed, Windows Phone is fantastic, etc.
I work in downtown Los Angeles. I was on Sprint until I just switched to AT&T and the Titan. Sitting in my office Sprint's 3G service was terrible, almost non-existent. But I could switch to 4G on my Evo and consistently get 5Mbps+.
In this same office on AT&T I get...wait for it...wait for it...I'm still waiting. I get nothing. I can make calls just fine, but the data speed is so terrible that it's rare that a data request doesn't time out. I get spurts of signal here and there, but it rarely goes above 1 bar. Even at 1 bar I get no data throughput.
So I go outside and get signal, just 50 feet away from where I get nothing in my office, sitting next to a big *** window. Walk to the other side of the building. Nothing. The other side. Nothing. Walk outside...signal.
Then I go to lunch today. Walking through the area I was getting signal before...I get nothing. Walking...nothing. Sit down at a sidewalk cafe, near the window. Nothing.
Apparently AT&T's HSPA network is incapable of penetrating glass or going around corners. I hope their engineers got a bonus for coming up with such cool technology.
All kidding aside, I don't know if it's AT&T or the Titan. AT&T claims they are working with HTC to resolve the issue, but I'm sure that's one of their many canned responses.
At home, 27 miles north of downtown LA, I get 2-4Mbps. It's not 4G by any stretch of the imagination, but at least I'm able to use the phone.
What really sucks is that there is just enough "4g" signal that the phone won't drop down to Edge. I've seen it drop down to Edge a couple of times, but it was just for a second or two.
Effectively for half my day I'm unable to use my data plan. Very sad. I hope a resolution is in the works, otherwise I'm just going to have to keep screaming at AT&T until they...well...until they keep ignoring me.