I'm interested in why you didn't just get a SGS2 Fox, was it Sense that made you go HTC?
I hated the look and feel of the SGS2. It just felt horrible to hold and I didnt like the look of it. I'm also a huge fan of the Sense interface and would really have missed that by moving to the SGS2.
I'm well aware that its a great handset - but it wasn't for me. It reminded me of a fully loaded Toyota Avensis. Sure, its got everything, it wont ever break and the spec is fabulous but it just feels cheap.
So far the only downside of the Sensation versus the GS2 that I've encountered is the screen. Everything else appears to be a non-issue in daily use. Battery is the same as the Desire, which I was used to. I couldn't care less about HD Video recording - its a phone, what exactly do I want to HD video anyway - and everything I've asked it to do thus far it has done lightning quick.
I'll see how its doing for speed once i've filled it with crap in a months time, mind