I started this thread so here's a little feedback:
Security: I had no issues and I didn't feel insecure, but I also had nothing in my pockets, didn't carry anything, didn't drink much and didn't stay til dark. I stayed most of the time besides the first large VIP-Area at that end of the street where they start. Also walked the whole street thru - no problems. Didn't stay til dark because of the concert in the stadium.
VIP: The common price for VIP seemed to be 200-300 peso, some offered free drinking for 500p. I stayed on the street but one could easily find a VIP with decent atmosphere.
Vejigas: Normally no problem. But some of the guys were drunken enough to hit with all force and that hurts. Men are not a target but if you a woman with a nice butt - watch out !
Bierprice: 30 peso for a lata.
Concert: A concert of Prince Royce in the stadium free of charge. Start at 9pm. Again feeling secure and comfort, 10 m from the stage. In Youtube there are videos from the concert, search for "Prince Royce La Vega".
Accomodation: I stayed at El Rey, nice rooms and friendly staff.
Would I do it again: Yes, but only if the concert is interesting.