The brand is the MAIN factor. Then comes the outer finish. The models do not differ much on the first view. And all of them look the same when theres a silicon case around. And honestly, who cares about hardware other than camera, number of cores and clock frequency?

I think for the mass, the phones which are cheap to get from your provider as bundle are the most successful. If the phone is advertised well you'll probably pay some extra money.

For me it was the hardware keyboard in the past. Now it's the OS, even if it's jailed in a poor device. But....you can ssh on it