Visited hear with my 4 year old son and parents. Decided not to book in advance as we had some "buy one get one free" vouchers from Tesco Clubcard. This certainly saved money but meant we had to queue longer than those people who had pre-paid (and only received a 15% discount on the advertised price). Certainly the cheaper option but there is a risk you won't get in if the place fulls up as you are not the priority so be warned.
I have mixed feelings about this attraction. First the positives:
My son loved playing with the Lego which is everywhere - especially enjoyed the tower/earthquake testing and car building/racing. The Kingdom Quest shoot em up/chariot ride was good (for us older kids) as was the 4-D movie. We did not get to take part in the Master Builder session but it looked good. The huge "pools" of Lego to play with were a hit but a bit too full on in my opinion.
Now for the negatives:
Considering it only opened in March 2010 it looks very dated and there are lots of bits missing from the displays. The car building was chaos as was the general feeling about the whole place. I think they let too many people in and it simply reminded me of a kids soft play area with Lego thrown in - same level of noise too. I expected more especially for the price paid and the Lego brand. The Cafe did not have enough seating and was overpriced (£2.50 for a white bread cheese sandwich - c'mon) - nothing really aimed at kids which was a real surprise given this is a kids attraction. I thought there were not enough staff on hand who could have helped with other ideas for building things from Lego. The Fire Academy was a small soft play gym was unsupervised meaning there were far too many bigs kids knocking over the younger ones (lots of tears).
Overall, I expected more from this place and felt they could have used their many models sold in the obligatory shop to provide large displays of what Lego has to offer. Would not return in a hurry.