I have been twice and never got on a ride due to:
-Price, I feel it is on the expensive side
-Queues, we were going to do the Wild Maus last year, but it had like a 45 min queue!
-People, they squeeze in way too many people, you simply just can't move. Every step you take, you end up with somebody in the way
-It is a tourist trap
But it is the best themed Christmas attraction I have ever been too and it does have some very good rides.
I have been told if you go earlier it is not as busy, but the last two visits were complete hell and when you add up the cost of the train tickets and a few rides it is very expensive. I guess if you are close to London or are in London and you have two adults with a good level of cash, but when you take children along, the cost does escalate. I did the calculations and last year to take 2 adults, 2 kids and do 4 rides each, we could have purchased 2 Merlin passes as our MAPs only cost us £75 due to the January sale. Just like any trip into London, it always ends up costing you a hell of a lot more than you