I agree with brucejr. Gotta be a way to define and quantify "fewest dropped calls". That would seem to be pretty straightforward, but the variables (geography, handset RF capabilties, carrier marketing spins) make it a bit of a muddle.
Ultimately for the consumer is comes down to the very subjective "what works best for you" decision, but it would be nice to have something trustworthy to reference to make that choice.