Question about rims?

I'm looking into getting some new rims for my Trailblazer EXT. it's an 04 and Black. I'm looking at possibly 20" or 22", anyone have some on theirs? If so, what kind of offset are you using and have you had any issues? Thanks for any insight you can provide.

If using 20" - 20X8.5 - suggested tire size 275X45X20
If using 22" - 22X9.5 - suggested tire size 265X35X22

I have ordered 22" wheels, but many suugest 20" are better.
Cant wait to put them.. shall post some pics once I get them