If your coming just to ski the summer park you will be dissapointed. I live never really going up cuz of the lameness. LIke htey said, a couple rails and a jump. But if your coming for other things like biking, lakes, drinking, dirt jumps, dirt skiing, golf, hiking, and patios then you'll be ok. I wouldn't base the entire trip around the summer park though cuz its not really worth it if your coming from further than Vancouver, but Whistler is super sweet in the summer and there's tons of other things to do too.
So yeah, come up.