Putting aside the fact that AT&T may end up purchasing T-Mobile (here’s hoping it never happens), and looking at just the quality of use on the phones on the networks they’re currently on:

4G Data Coverage – Sensation wins because the Atrix still has it’s upload speeds throttled, and there’s no reason to believe the Sensation will share this as none of the current T-Mobile “4G” devices are. Also, if 14mpbs is the peak download speed, then we can expect somewhere in the realm of 6-10mbps on average, and that’s spanking even Sprint’s WiMax offerings in both speed AND coverage.

Display – Sensation wins by a slight margin, only because of the additional screen real estate. 4.3″ qHD, only marginally larger than the Atrix but smaller than the Evo, contoured gorilla-glass? Sign me up.

User Interface – Sensation probably wins here too; the newest version of Sense appears to be pretty frickin’ awesome, while the Atrix’s UI hasn’t gotten too many accolades to my knowledge (the opposite in fact). Also, the Atrix 4G launched with Froyo, correct? And the Sensation will launch with Gingerbread, right? Win.

Battery – Atrix wins. Seriously? HUGE difference, and I must say I’m disappointed to note it.

RAM/Memory – Atrix wins spec-wise; even if you can put a 32GB microsd into the Sensation, less than 1GB of RAM is just poor form nowadays.

Camera – Sensation wins here; anyone remember the 8GB camera on the Incredible? HTC does these extremely well.

Processor – Tough to call; the benchmarks on the Sensation have been less than impressive, but it’s tough to properly measure them without both final software iteration and updated benchmarking tools. I’ll call this one a tie UNTIL there are better comparative measurements.

Overall, I’d be more partial to the Sensation for several of the reasons above; add to that the fact that the monthly bill would be smaller than the equivalent on AT&T and the propensity that Ma Bell has for blocking non-Market app installations, and this is essentially an easy pick.

Again, just my opinion.

Either one of these phones would be great on Verizon but crippled on ATT.

As for the phones – Atrix hands-down. Tegra2, more memory, laptop dock – the Sensation is beat.

The only thing the Atrix is missing to make it the absolutely perfect phone for me is a physical keyboard. I’m praying for one of those add-on keyboards like the iPhone has had a couple of for the last year or two.