Boost Mobile is a subsidiary of Sprint so if you like Sprint, Boost Mobile may be for you.
One thing that I hope is that Boost have dropped is the requirement that you had to have a Boost/Sprint phone before they would sign you up. Of course they were happy to sell you an old BlackBerry too thus depleting Sprint's old phone inventory.
I've been a Boost customer for years with their IDEN phones and just last Feb got their BB Curve 8530. Never had a problem out of them. Call quality is just as good as AT&T and never had a call dropped.