We went last year just after Thanksgiving. We were on the Windstar, I guess our biggest problem was having to schlep up the stairs when getting off the tender. When you are carrying snorkeling gear/ shopping purchases/video cameras, etc up 23 steps (yes, I counted) it can get pretty tiring.
Also, i rained quite a bit. No way to really forcast this, but the rain stopped on our last day in Moorea. The timing was perfect.
However, we liked the smaller ship (other than the lack of a decent pool), a lot less hustle and bustle. Food was great, and service was quite good