Or rather, Rain Dance Teams vs. Sunny Day teams.
Which do you prefer?
Which is more useful?
Personally, I like Sunny Day teams more. Thats because I like things like Shiftry, Tropius, stc who go from mediocre to down right deadly under the sun.
However, Rain Dance teams work much better. I speak from experience and I'm sure others will agree with me that Rain Dance Teams are better overall in battling.