I live in the Twin Cities and have Sprint. I am paying less now for my plan (my wife & I) than I was with AT&T. On Sprint, we both have unlimited data & texting and share 1500 minutes.
On AT&T I had unlimited data, 50 texts/mo and my wife and I shared 550 minutes, she didn't have any data or texting. Also free nights and weekends begin at 7pm on Sprint, instead of 9pm with AT&T
Again we pay about $20/mo less now with a bunch of additional features than we did with AT&T.
It makes no difference to me, but you may want to at least check pricing first, if that is the deciding factor in which provider you choose.
If you do decide to go with Sprint, you should check out the EVO coming out in a month, it looks completely incredible.
http://gizmodo.com/5500343/sprints-htc-evo-the-first-ever-4g-phone-meet-the-new-terrific
EDIT: Didn't see the post above before I replied, sorry