I've seen a lot of negative reviews online but I really enjoyed it - we were warned to bring rugs and cushions beforehand and managed to get them on the Hornsey to Ally Pally train at rush hour with no problems at all, so I'm not quite sure what the review above's point about carrying them on the tube is.
Thought the sets and actors (a camel walking through the Great Hall!) were really impressive and the large number of people in the audience was really suitable. The one problem I had was that I don't think it was clear how many food stalls there were which resulted in some very long queues on Friday at some stalls. We took a chance on there being more further inside and only had to queue for 10 minutes.
I think we were at a advantage with the location of the event for the film's length though, it would have been a nightmare getting back had we been travelling across London and not hopping on the bus down to Wood Green. Also meant we could pop back home for 20 mins on our way home from work to pick up costumes and seating.
It was my first time but I'd definitely go again. Lawrence of Arabia had always been one of those films I meant to get around to seeing and never had done - and a great way to see it for the first time.