HI I live a short distance from Grapevine where Lego in Grapevine Mills is. It is VERY small. There is a small "dumbo type" ride that is made from legos. there is also a large area where kids can play. There is a ride at the very beginning that is loosely like TSMM. I say very loosely.
Is it "worth" it? Well that is up to you to decide. However I think it might take 2-3 hours to do everything and that is if you are really really slow in it. It is very small.
My family went not too long after it opened. The boys had fun. It was a neat experience, but to me it was over priced for what it was. I wouldn't make a special trip from San Antonio, unless you have other things you want to do.
I thought it was very small and overpriced even with a discount. I would not make a special trip for it from San Antonio and I have three boys who love Legos. We have been to LegoLand and loved it. This was a disappointment.
It sounds like it is similar to the one in KC. It is pretty expensive, but my kids actually found it to be pretty fun. I would not make a special trip just to visit legoland, 3 hours is probably the most time you could get out of it.
I agree with most of the Previous Posters. We were in the Grapevine area for a convention (for my work) and took my son (8 at the time) and my niece (5). Even my niece loved it. It was overpriced, but you can sometimes find deals online.
I wouldn't drive to the Grapevine area JUST for Legoland. If I happened to be in the area, I might visit. (PS, we live 5 hours from the Grapevine area). But, it might make a fun weekend getaway with a few other things. I thought the aquarium was pretty neat, and they have an ice skating rink in the same mall, I think.