I'm about to do a favor for someone that is very well connected and this is what they offered me in response to my favor.
What was the favor? Are you donating a kidney? 
The answer depends on what your goals are. If it's about your friends, they are going to be winners any way you choose. If it's about the golf, then I would say it's a toss-up between Philadelphia and Southampton. [Sebonack has no bearing on breaking the tie.]
But, if you are being practical, an invitation to Augusta National is much harder to come by. Neither Pine Valley nor Shinnecock is really that impossible to visit for someone in the golf business who knows a lot of people. Augusta members are not nearly as numerous, and less likely to invite a "golf business" friend, at that. And for your friends, it's almost certainly a once-in-a-lifetime chance. So, I'd recommend Augusta.
Thanks Tom, I greatly respect your opinion because you've studied these properties in great detail. What you posted sums up my initial thought process. To answer your question my goal is to play the best golf courses. Do I think I'll be invited to Augusta again? Honestly, I do and I hope I'm right! Will I be invited to stay the night on club grounds again? Play multiple rounds? Maybe. Honestly I don't want to play Augusta as is, I believe the club's leaders made some bad decisions regarding the placement of trees, length, and rough. I believe and hope that in the coming years Mr. Payne will rethink many of Mr. Johnson's bad decisions. Until those bad decisions are reversed, I'm really truly not that excited about playing this version of the tournament course. Now the "experience" will be grand regardless and I'm not counting that out. Will I be invited again? That's the million dollar question.
I don't want to sound like an ungrateful idiot, I'm just trying to be honest with myself.
It's hard for me to pass up staying and playing at PV/Merion. I worship Ben Hogan, I have every single Ben Hogan book (bad and good) and I also worship Bobby Jones. They are my idols, I spend most of my free time reading about them and I know that would make you think I'd play Augusta (Jones). To me though Jones and Hogan made history at Merion and I can't stop thinking about that. Plus I'd be playing the course in U.S. Open like conditions...
It's a tough decision because I'd also be playing South Hampton and Friar's Head on long island (Different guy).
It seems like an easy decision until it's real.
I respect all you guys so much and I truly appreciate your thoughts. If I hadn't played them so many times Cypress/Pebble Beach/SFGC might be my number one choice!