My son received this for his 7th birthday recently, having requested the Toy Story Lego series of kits. He loved building it, although it is quite a long build for a 7-year-old (the pieces come in 4 numbered packets plus the characters). There are a few fiddly bits, but nothing he needed help with. He was ecstatic to get a Lego green alien, as well as the other figures (and the set is not remotely appealing without them, really).
There are several annoying bits.
1. Rex (the dinosaur) can only fit in, looking through the roof of the rear section, by removing the roof. When you do this, several other bits fall off so you have a bit of a repair job.
2. The main problem is the firing mechanism for shooting the pizzas out (!). The strength of the bit of elastic provided is such that the whole chassis of the truck collapses under the strain of pizza firing, almost immediately, and I spent much of the day rebuilding it when my son ran out of patience. When it works, the pizzas fire a disappointingly short distance.
Overall he still loves the toy, both construction and play. But he has found it very frustrating, since the play function is not really fit for purpose.
He also received the LEGO Toy Story 7595 Army Men on Patrol
kit (small, but absolutely adored this very simple set, and plans to buy a second of the same so he has a bigger army) and LEGO Toy Story 7590 Woody and Buzz to the Rescue
(his favourite, and the one I most highly recommend; the pull back action works brilliantly and the play value is even more fun than the building).