Thanks for the response. I called and spoke with someone (okay, 3 different people) at AT&T, and here's what I got from them.
Basically, there is a "4 HD" limit, however you want to cut that up. You can watch up to 4 HD programs at the same time, or record 2 and watch 2. The internet connection is not affected by this, nor does it affect this.
They couldn't tell me specifically how far my house is from the cross box, but they said that it shows that my house is eligible for the U450 package and the 24 Mbps internet, so I must be close by virtue of that. Not sure about that logic, but that's what they said.
I'm still weighing out the options.....I think cost-wise, it'll be a wash. There ARE some nice features with the AT&T offering, as long as it doesn't suck.
Thanks for your reply!