I'm registered with Wolf and played quite a bit at Bunker51 and have to say that Mr. REMSoft is correct.
The crowd are good and most of the staff are ok. The trouble is the venue itself- it's not set out to be used by airsofters who understand the principles of suppressing fire, or anybody else who works out that shooting at the place where the baddies come from keeps them hiding. Owing to how they position spawn points, the team assaulting from the 'prison block' have an immediate field of fire on both doorways their opponents will be coming out of leading to some of the dullest and most static games I've ever played. While mashing away on full auto is often quite satisfying (particularly if you don't do it often like me) it gets dull. This brings us to another point about Bunker51- it's TINY! There's no chance to try and play a tactical game or use cover beyond as a place to have a break while the hailstorm of bbs rattles on, particularly on an evening when more than the usual handful of rentals rack up. This is why the "Zombie" round they play at the beginning is a lot of fun; it's semi-auto, there's a little more sport involved, some actual aiming.
Ultimately what you're paying for is a venue that offers games within the reach of public transport, something I value highly since EBZ Bexley closed. I shall, in all likelihood, be making a few more appearances at Bunker51 but only to keep my UKARA current.
Sorry if sounds massively flamey. I've always enjoyed the chatty environment and made some friends at Bunker51 but the facilities are what they are.