Good question, I also bought for the first time a red zone ticket.
Regarding viewpoint and proximity to the band: as the stage setup is practically the same - judging from pictures and youtube movies - as during the I&E Tour, I would say the best place is probably the GA. I was doing GA in Antwerp in 2015, and entering the arena a few hours before showtime, we were still able to stand at the rail on the center walkway! Seeing the band performing meters away was an impressive experience... I fear that Red Zone will not give us the same close quarters experience... Nevertheless it will give you a great view on the screen, which I didn't have in Antwerp as we were actually too close to the screen, and a reasonably close position to the band. A true compromise.
Regarding the actual Red Zone amenities: there I hope it delivers what it promises. Easy access to the venue, maybe a backstage tour (definitely interested!!) and the convenience of having the bar close-by. All this without the need to queue for several hours.
Please let me know how was your experience! I will do the Red Zone in Cologne on Wednesday 5th.
All the best.