I've seen tons of concerts by artists of all different genres at venues from 100-person clubs to 40,000 seat arenas, and B.A.P managed to blow them all away. They made good use of the venue and while it felt as intimate and personal as a smaller venue, the lighting, costumes, and performances could've filled a huge arena.
Their vocals were clearly live, which I can't say for a lot of other k-pop artists I've seen in concert, and they sounded very passionate and even better than the studio audio. The live drums and DJ made the songs sound even better.
Their performances were very powerful and the members were clearly enjoying themselves onstage. The solo stages were great too, with Himchan showing off his improved vocals and Zelo wowing everyone with his dance moves.
Even though none of the members speak fluent English, they still interacted with the fans a lot, and had a translator for when they couldn't find the right words to use in English.
The show was over 2 hours long, plus a couple encores, and it was worth every penny I spent and more.
With regard to the venue- it was fine, I got in without any trouble. The merch stand was disorganized, and they were sold out of many items, which was annoying, but I still had a great time.