I went once to the London one.
Still got the T-shirt:
[img]http://www.medwaypvb.pwp.blueyonder.co.uk/scans/war1.jpg[/img][img]http://www.medwaypvb.pwp.blueyonder.co.uk/scans/war2.jpg[/img]
I didn't actually think much of the 'experience';
1. Never actually saw an Alien, possibly due to the large group I was in blocking the view.
2. Amongst our group were some young kids (age 7-11 approx), who spent most of the time screaming/crying (parents stayed outside).
3. During the running about, we had to run down a corridor and around a sharp bend. Just around the corner was a set of stairs, not lit/highlighted at all.
The young girl in front of me tripped up the stairs, I then tripped over her and the big (>6ft) guy behind me landed on top of me, his leg driving my left knee cap into the front corner of one of the steps.
I limped around for the rest of the day, just thinking I'd bruised it.
Two years later I still couldn't kneel down on it.
Even now I can't kneel on it for more than a minute. I guess something's not quite right in there, but it's not enough of a problem for me to get it looked at.
My G&P/MiM+TM M1A1 PR build guide