On it's own with just butter? I've had really amazing lobster, I've had rubbery inedible garbage. But crab is usually just crab. King crab, snow crab, it doesn't matter, it never reaches the same peaks that well-prepared lobster can.
But broaden the category to lobster/crab bisques, cakes, and other products.. I love a good crab cake or a good lobster bisque. I can't choose!