My family has done WDW much more than Universal, due to the fact our DS has not been mature enough to enjoy all the attractions at IOA. He is now 10 and finally into thrill rides, so we are planning a trip in Oct. for our anniversary and can't wait! We also plan on spending 2 days of our Thanksgiving trip to WDW there. Since we have been to both, I'll try to help with what little my opinion can.
I definitely don't think you will be disappointed in PBH compared to WL! PBH is the greatest! You're son probably would prefer HRH, but I don't think the adults would. We are planning on staying at HRH in Dec. only because we want club level. If they both had club level , I wouldn't have to think twice. PBH for me!!! I have to be fair and say, this will be our first trip to HRH, but I'm not really looking that forward to nonstop rock and roll 24 hrs. a day. If I were 17, it would be different. As far as the park comparisons: I always reccomend that my family and friends who come to visit us (we live in FL by the way) take there teens to Universal Escape. Not so much for Universal but for IOA. On the other hand, I reccomend that our visitors who are all adults or have small children go to WDW. The 17 yo. will not be disappointed, but the adults may. Don't get me wrong, I don't think you will be disappointed in Uescape, I just think you may go home wishing you hadn't completely skipped WDW. But I'm biased, I'm an Epcot addict!
As for the beach: If you are looking for smooth clear water and huge white sand beaches, go to the Clearwater, ST Pete. area. If you are looking for waves, hit Cocoa Beach. It depends on what you're look for in a beach. My family happens to disagree on this one
Sorry so long, but I hope I addressed all your concerns.