YMCA Masters vs. USMS

I live in Western PA, and most of the meets around here are YMCA sponsored masters meets. I know the Y program is a separate system from USMS, and you don't have to be a member of one to join the other. A lot of people around here swim in both systems--Y for local meets, USMS for national meets. I'm wondering, among other things, if anyone might know if YMCA masters has any ongoing TOP 10 listing the way USMS does. My experience with Y swimming is that the competition is maybe just a wee bit less competitive and hardcore. Then again, my only USMS masters meet was Long Course Nationals two summers ago, and that was a pretty high profile meet. Has anyone else had experience with both systems? What do you think about the differences between them? Are they ever likely to merge like pro football circa Joe Namath's ear?