I also switched from a torch, I installed mango first thing and can't imagine having the phone without it.
I thought I would miss my torch, as I was a big bb fan, but I don't miss it at all except for maybe a few features that I suppose I can live without.
Wp7 is a very refreshing interface and easy to use, my only concern is that I went from one platform that didn't have slot of apps to another. I just hope that once mango goes mainstream, the apps will start flowing. The apps that are around are very good quality and much better than bb. This also takes much better photos than my torch, and is much more fun to use and handles my work stuff just as well.
Enjoy.