I can tell you that I rooted my phone two days ago (on telus here in canada).
after trying several roms for cdma I finally tried a gms rom and it works - funny - telus was always cdma, but I guess they're gsm now for the hero at least.
anyway, villain 5.5 was first try, worked great!
then wiped, put on sensehero 2.2 (whatever latest stable build is) and liked the UI changes (purely cosmetic I think though) but missed all of the cool extras built into villain 5.5 like the keyboard hacks and tons of other settings additions. I used sense 2.2 until about 10pm last night and found it SLOW, irritatingly slow, unresponsive, and frustrating. was really disappointed - maybe I had a unique usage case or something. but it was pretty basic, installed some of my favorite apps, but it sucked compared to villain right from the start as far as performance goes.
went back to villain 5.5 last night after a wipe (and oddly the htc widgets weren't there any more, first time I installed villain 5.5 the htc widgets were there out of the box?? ran the "get more htc widgets" link which kept saying it couldn't connect (yes I'd setup adb etc by then, that wasn't the problem) but turns out that it actually did connect and did install the missing htc widgets (yay!). so I was ready to go wtih villain again and yes, it really is dramatically faster than sensehero 2.2. Still using it now. in some ways faster than 1.5 telus stock, in some ways slower, don't know about battery yet but I'm sure it's using more so far (will start messing with hacks to improve battery life though).
so for me, villain wins by a ton. was really disappoined that sensehero was SO unresponsive on my phone compared to villain, but both times I installed villain 5.5 it proved to be much faster in performance.
So your mileage may vary though...
note: yes it's my first post here - hi everyone, name's Don, happy hero owner. will be leaving my wife's hero unrooted for now to see if/when telus comes out with a 2.1 release officially for it though... don't want to screw anything up on her phone LoL.
PS: are there any other useful alternatives to villain and sensehero for 2.1?