There's another reviewer that mentioned the Concrete Mixer will come apart if played with "robustly". My son does this with the mixer and I it does the same thing. Whilst this is a feature of the mixer - I don't mind because:
a) it is helping to teach my son that being gentle with toys is beneficial.
b) it is helping him learn to rebuild his own LEGO toys (thus feeding his creativity and saving me the job!)
The mixer is good; the mixing barrel can be tilted, the chute moved both horizontally/vertically and there are lots of tiny grey circular pieces representing the concrete. The roof of the cab is easily detachable in one piece and the additional mini-figure with the wheelbarrow is a nice touch.
Overall this is a worthy addition to my son's collection and, as with all his LEGO, its a major part of his current playtime.
Something else - my son is 4 (a little young for this particular item if you go by the guidelines) and loves it. His cousin is 10 yet admired and played with it during a recent visit. He's now asked for one for his birthday. Seems like it's a good age-spanning item.
Definitely recommended if you've got a little LEGO lover in the house.