Great question. I was just speaking with Whitney Trimble on our Outerwear team and he confirmed what you said about the waterproofing - both garments come with the same 2-year limited waterproof warranty although I can tell you from experience, if waterproofing is your main concern, go with the Tour Collection jacket. They used new material this year that allows the water to bead up and run off the jacket. It's pretty impressive. In addition, all the seams are sealed and it comes with a waterproof zipper. If you play in the rain a lot, this is your jacket.
Many of the features I just mentioned, however, also add to the weight. The waterproof zipper, the Cinch system, the tafetta lining, elastic bottom and exterior fabric all make it slightly heavier than the Performance Light jacket which has a mesh lining, as opposed to the tafetta, and is more along the lines of a windbreaker.
The Tour Collection jacket will be more waterproof and probably slightly warmer but the Performance Light will be lighter. I guess it all depends on what features are most important but you really can't go wrong. I hope this helps!