I know the Mall quite well, not been in a few months but it's a good laugh. Better with fewer people, otherwise it bogs down too quickly. If you've never been to the mall before, bring a torch, it is very dark downstairs. Quite fond of Combat South and Zed Adventures Battle Lakes as well. I think airsoft is good for a laugh with a bunch of mates, certainly not something to be taken seriously. You can literally see the bb's coming towards you and dodge them, no chance of that with real bullets.
Also beware the temptation to buy lots of guns straight away, get one that you like the look of and run it to death. Then upgrade it if you're still playing .