I'm a regular there and a member. I go nearly every week without fail (although I have been on holiday recently and had a tat and I would rather wait until it's healed just in-case it gets hit and knocks a scab off).
The membership for £60 is worth it. You save a great deal of money on skirmishes, you get to attend members nights (which are great because you just go in and game as everybody knows it and there are no newbies there) and you get free stuff (mainly food and t-shirts haha).
Overall I have been going since around March every week and I must say, the staff and marshals are friendly and they are tough when they need to be i.e. somebody cheating they will warn them, happens again they get kicked out etc etc..
Even for cqb, 350fps is enough and even though its single shot, you still have great fun and it helps your accuracy too, rather than just mag dumping down range to pin somebody down.
There are supplies on site, ammo and tools too. If you feel peckish you can walk 30 seconds down the road and you can find a few shops, rather than having packed lunch or what they have on site if you were at a woodland.
Long story short, if you can go to halo then go. You will love it. Its cheap, its fun and the staff are great!
The variety of game modes is great too, from stealth games, to ctf and even zombie games, there is something to make you have a great time. My personal favorite is the disco game.