Smallmouth are my favourite fish to catch, and largemouth my second, but the gap is big.
Here in Ontario (Canada) I fish mainly Muskoka, Haliburton, the Kawarthas, and Lake Simcoe, and largemouth just don't typically get that big up here, although they are very abundant. Smallmouth on the other hand have quantity and quality. We've got hundreds and hundreds of deep, clear, high dissolved oxygen lakes so they're always nice and healthy. Catching a half dozen 5-6+ pounders in a single outing is normal on parts of Lake Simcoe, for example.
I'm sure if I lived in Texas, or the Deep South I'd like largemouth more...