http://www.pcmag.com/article2/0,2817,2394224,00.asp#fbid=S3sTmh6q7Or
I am switching to Sprint from AT&T because it will save me $75 per month compared to Verizon (5 iPhones on the family everything data plan plus 1 individual 450 min plan with a 23% corporate discount). I am unhappy with the number of dropped calls, delayed text messages, calls going automatically to voice mail, etc. with AT&T.
Good page...here is the image of the graph:
