I did it for the Nov 2017 show in Chicago. We had to be there by 5 pm and you were allowed to bring two things to sign. When we went in, they wanded us and you had to sign in to prove you were on the list. Then they gave us a DT bag, a small poster of the band, a plastic badge, and one of those power bars for charging your phone. It was cool talking to the guys for a bit and they were all very nice. The only minor complaint I had was that when it came time for the photo I literally walked up to the band, said hello, and the second I turned around the person taking the photos was already saying "Here we go...3..2..1..." CLICK! before I even had a chance to get into position. Regardless, they later email you the link for the photos. As others here said the VIP gets you a better seat and I could see everything really well (I was in the pit section).
I also did the VIP G3 2018 show in Chicago and was first in line for the M&G. I got to talk to JP, Joe Satriani, and Phil Collen for a longer amount of time and they were all very cool. Pretty much the same procedure as the Nov 2017 show in terms of the overall procedure. I also got to speak with the guy who was in charge of the M&G who was very funny and really interesting.
I had fun with at M&G and don't regret it for anything. Best of all, I have great memories and some autographed stuff on my wall. It's not something I would do every time however as it would no longer feel special, but if you're on the fence I say that life is short - go for it and have a great time. It's definitely worth doing it even once.