I had one. But my GF nicked it and now I get to touch it once in a while whilst I have been relegated back to my iphone 4.
Personally as a real Apple fan, I think the Sensation is awesome.
The phone physically looks great. The Sense UI is top notch. The lock screen is megacool. The screen is brilliant. It's probably a tiny bit worse than the Retina display on my iphone but the sheer size more than makes up for it.
The camera is the best I've seen along with the Samsung Galaxy S2.
When it first came out it had a few bugs which were very annoying but those have now been fixed.
So....where does it fall down? Well if I am being picky the bevelled screen makes it hard to put on a screen protector. That said, the display is gorilla glass so in theory I shouldn't need one. I just feel safer knowing there is one there though.
Battery life is worse than my iphone but probably par for the course for a smartphone. GF has to charge it every day without fail. If she uses it a lot then sometimes 2x a day.
Compared to the SGS2, it's not as fast on paper but 99% of people will never notice. Plus it feels more substantial than the SGS2 which looks a bit plasticky and like it would smash if I dropped it.
Finally in answer to your question about watching catch up TV. I assume you mean ITV player, BBC Iplayer etc. In which case yes it will let you do that.
In short the hardware/software is better than the iphone 4. It will be interesting to see what Apple pull out of the hat next month with their new phone. If you are patient you may want to wait to see if as a result of the new iphone, the Sensation prices are cut.