The kids absolutely love this lego set. I wouldn't say it's an easy one to assemble. My boys are 10 and it kept them occupied for a good couple of hours. I think they enjoyed the challenge.
One thing to watch out for is that the battery box takes three batteries in each side. They put three in the top of the box after they has finished the build and wondered why it wouldn't work. Once we'd figured this out and got it working they played with it for days.
Lego is expensive these days but they are still getting a lot of play out of it.