Since I just upgraded my smartphone a few weeks ago, I did some research on which smartphones had the best cameras & IQ, as that was one (among many) of the considerations for me.
People interested in camera IQ as one of the key features when purchasing a new smartphone may find this recent comparison reviewing smartphone camera IQ by PC World interesting:
I believe some Nokia smartphones have 12MP cameras built in, that are the best currently available built into a smartphone, but the Nokia didn't suit my needs as far as some of the other critical smartphone features are concerned, so I opted for a Samsung Galaxy SII, as it was a better overall match for my needs/wishes, and still had one of the better cameras currently available in a smartphone.
This is like asking which is faster, a Honda Civic or a Ford Focus? It's like an illegal question. For all practical purposes, they are equally inferior.
Or alternatively, why not ask if you should buy New Balance or Nike shoes to walk from New York to Los Angles. Get on a plane, get on a train, or get in your car. Could you walk that distance? Sure, it'll take you a while.
Yes, they are handy for casual shots. But why are we comparing smartphone camera quality for casual shots? Comic amusement I suppose.