For convenience it's amazing. I love, love, love that every time I go back to the room or when heading to the pool or wherever, I can grab a quick drink or snack that's already paid for.
We do Deluxe Dining as well, we use the lounge offerings in the afternoon (and possibly a snack credit) for lunch every day. Some days we have breakfast in the lounge as well. This opens up a wonderful opportunity to use those dining credits for Signature meals and shows.
We have been blessed in September. In our past 3 trips it rained for one afternoon on each trip, and even then only for an hour or so. We love going toward the end of September, it's cooler, there's less waiting on rides, just less people in general (we usually clear out right before the Food & Wine crowds show up). Last year it was a little busier though. I'm not quite sure if it was a fluke or a trend, but it still wasn't busy enough to cause an inconvenience.