Out of the 3 locations, I'd say Miami would be much better than the other 2. Then again, I might be completely off base here!
Lots of POTs in West Palm but you'd have to pick your event(s) carefully. Things like the Barrett Jackson car auction (I think one starts this week). If you don't "fit in" you will not have much luck. I'm really not a fan of the area. Generally speaking, not my kind of people there.
The problem I see with Lauderdale is the POTs are almost too old. I guess depending on the ages you seek this might work out for you.
Miami is much more vibrant and "happening" if you ask me. Even for middle-aged people like me, it's the best of the 3.