We took our son (5 yrs) there for a birthday party and I was pleasantly surprised! We ended up going back a second time w/ all 3 of our children (5,3,1). It's like going to a mini theme park. There is even a ride into a tunnel with lego dragons. There are lots of things to see and do - including a "make your own race car" area, and a play area like an indoor park (tunnels and climbing stuff). There is a movie but we did not see that. There is a Lego jungle with all kids of Lego objects. There is a Lego "factory" which is a little silly but our kids loved it. There is of course a store on the way out but we skidaddled through there and the kids hardly noticed because they were so tired from playing.
It's definitely a little expensive, but I think it was a lot of fun. Get your money's worth by going early so you can stay a few hours (we have a child who still takes naps so that timing was important to us). Get a coupon or get your ticket online for a small discount.
I think it was great for us because our 5 and 3 year old boys are obsessed with Legos. But there were also lots of girls having fun there too. They love to build stuff and learn and soak stuff like that up.
Definitely a destination place, fun for us once or twice a year probably from now on (we live 45 mins away).
Have fun!