Pros: donates money to good causes
We recently switched my wife's cell phone provider from T-Mobile to Credo. I've had my eye on Credo for almost a year since I found out they donate money to good causes - 1% of charges plus they give you the option of rounding up your bill to the nearest $1/5/10 and donating the difference. I'm still on a contract until April, but my wife switched over and has been happy with it.
The coverage is just as good as T-Mobile. The plan isn't quite as economical - $29.99/month gets you 200 minutes with Credo and 300 minutes with T-Mobile. However, since neither of us ever uses 200 minutes in a month, it makes no difference to us. Text message costs are identical (15 cents per text unless you do a special plan). The free phone along with the plan was pretty good, nicer than the free T-Mobile phone (both have cameras, but the Credo one also has bluetooth), but the battery doesn't last as long.
Overall I really like Credo, and will be switching my service as soon as my contract runs out with T-Mobile as well. As long as I'm paying a cell phone bill, some of the profits may as well go to good causes! Oh plus they give you free Ben&Jerry's ice cream when you do stuff like agreeing to round up your bill. Mmmmm, ice cream.