Another thing is that you can ask for a "loaner" phone for a day or whatever. I know when I bought mine they gave me a standard phone and I was able to use that for a day to drive around town and make sure it works where ever I needed to try it. You probably won't get to try different models of phones with that, but you can see where the service provider does and doesn't work.
Hands down best service I have had with a cell phone company is sprint, more expensive and their customer service tends to suck although has become alot better in MN they seem to be the best Ive had. Other companys Ive had ATT, Verizon, Airtouch, T-Mobile and Cingular
I had ATT, it was fine, but We switched to T-Mobile and it'* great. $50 family plan, 2 phones 400 minutes to share. Free nights and weekends, free calling to any T Mobile customers, NATIONWIDE Plan. All i have to worry about with calls, is during the day, to non-t mobile customers.
The service is really the best, never one dropped call, awesome coverage, crystal clear calls, cheapest data plans out of any other provider, faster data plans over many other providers. When I connect my cell phone upt to my laptop I get 127kbps transfer rates on my laptop, althouhg not as good as what I get at home with broadband, but when travelling on the road and surfing the internet at double dial-up speeds its pretty nice.