I did get a look at the HTC Sensation, and even with just 5 minutes with the two phones, I got a good feel for why a lot of people prefer a stripped down true Android phone over the ones loaded with bloatware. The HTC interface has all this 3D spinning whiz-bang animation crap that totally turned me off. I'm sure I could eventually tweak it to make it more palatable, but it seemed to me that all the extra horsepower of the HTC's faster CPU would be eaten up by visual effects and crappy apps.
It takes no time at all to remove all the visual effects and apps and just run a very lean one with excellent battery life. I have the older HTC Desire HD, and I get almost 2 days battery life under normal usage - no silly visual effects, no Sense UI (replaced it with the Go Launcher), no auto-sync, auto shutdown of power hogs (like phone, wireless, sat-nav etc) and it's smashing!