I have been with AT&T for years and years now. I am not sure why I have stayed so long. They have overcharged me, double-charged me, limited my service, and done all kinds of the fun things some mobile companies tend to do. I have been hearing great things about Sprint lately, especially about their unlimited data plans and am definitely considering a switch.
Personally I am more interested in using an iphone on their service, but these free EVO's are definitely looking nice. Especially considering the 4G. Now, my area doesnt have 4G in most of it, but I am sure it will come here soon, and certainly when I am only a few miles from my home the 4G will work. :)
I have been waiting for a good opportunity to switch to Spring and this seems like a great time to me. Check out the link above and comment which phone you got!
There are some ridiculous deals on Sprint right now! You can get an Android™ powered EVO 4G devices on Sprint for free right now. Plus you can have activation fees waived for a new line of service and even free shipping.