For me, here are the advantages of a double bass setup:
1. If you like blasting, double bass has a better feel because you are dealing with 2 different skins for each beater. Hence, the response is more felt with that setup.
2. Triggers would love a double-bass setup than that of a double pedal setup.
3. Resonance! The room all of a sudden has richer overtones, because you hear 2 bass drums resonating instead of just one.
4. Looks. (Relative though.) I guess Tommy Lee has the best 32" and 40" kicks available in double bass.