I have been with Boost now for about 2+ years.
About 2 years ago, I signed up with there unlimited plan. I was with Verizon under my mom's account. She wanted to start charging me $99 just for a add-a-line because she talked so much.
I have had barely any problems. I did get hit with the text message problem for about a month or so, but it works just fine.
The voice quality is really good, but I do get a few dead spots in more rural Boulder.

I have owned a few different phones over the years. Started with the I215. Not bad for it' s time. I just wish that they would reduce the price of the I1.

So for my two cents, get Boost Mobile. It's a great price!