This was my first venture back to Technic lego, since I was about 10 years old. (I'm now 30.) Parting with the money was a difficult choice, but I have to say that it's money very well spent. You get to build two models: the main integrated tow truck, and a cab and trailer type model. Once I had sorted out the pieces into various types, I got building. Each model took me the best part of the day, and I got my children involved by letting them get the pieces in advance. Both models have great functionality, and my children had a blast using them to tow various dolls cars around, pretending that the Bratz had a blow-out etc. Taking the models apart takes a while too, but stangely it's all part of the fun.
I forgot how satisfying building Lego sets can be, and it's proved very educational to my children about how gears etc all work.
Ive just ordered the 8421 Mobile Crane!!