Lego Ninja Turtles Turtle Lair Invasion is one of the best investments I have made in terms of Lego sets for my children. My kids absolutely love both Legos and Teenage Mutant Ninja Turtles, so I thought this set would provide hours of fun and enjoyment for them. I was absolutely correct. This set provides a good building challenge for any Lego enthusiast. There are a good number of pieces and the steps are somewhat challenging. This is definitely not a beginner set but it is challenging enough for children with some Lego building experience. The feature of this set that is the most impressive is the number of mini figures that are included in the set. My children are able to recreate many scenes and are able to tell creative stories with the mini figures. Overall, this set holds together quite well even with frequent use. I highly recommend this Lego set for any Lego fans!