For 30 years I have been collecting and builing Lego, and for 20 of those have concentrated on the Technic and Mindstorms stuff of which I have probably owned well over 50 sets. In all that time I would say that the only Lego set I rate higher than this one is the Mindstorms NXT. This bulldozer is an excellent model - extremely well designed, challenging to build (most kids would definitely need some help), solidly constructed, and hugely fun! And it looks great too! The only *tiny* dissapointment for me was that the motors and connectors are not directly compatible with Mindstorms but I think you can use the RIS to send IR instructions to them, arguably making them more useful in mixing with the older Mindstorms kits. It has definitely been the most engaging Lego model for me so far and was worth every penny.