This was a birthday present for my 9-year old son. Delivered the day before so I only had the evening before to get it unpacked and built. No problems in that department though, as there's not an awful lot to do except fit the handlebars, pedals, stunt pegs and front wheel. The instruction manual gives clear instructions on all of these aspects if you're unsure.
There is a cycle multi-tool included in the box, but you may want to use 'proper' tools to make the job easier. I found a socket set and adjustable spanner made light work of the assembly. The only things to watch for are the pedals (which are Left Hand/Right Hand and need to be fitted on the corresponding side) and getting the front wheel on. The instruction manual says to "make sure the brakes are loose enough to fit the wheel" but if you deflate the tyre, it slips between the brakes without any adjustment.
I noticed the chain was extremely tight (no play at all), so it might be worth checking and if you find the same, just slighty slacken the nuts on the rear wheel to reduce the tension (remembering to tighten them up!).
As mentioned by other reviews, it's much more lime green than the yellow in the product picture. This shouldn't be a problem for any child, as it's a really funky colour. The forks are black on the bike I received. I have some images to upload which should be on the review soon.
I think there have been comments on the hard saddle too. OK, it's not the most padded seat I've ever seen but my BMX, when I was a kid, had a solid plastic saddle and it never bothered me. This is a kids bike, and they don't get bothered by insignificant things like sore bums!
Overall, great bike, funky colour scheme and easy enough to put together in 30 minutes max.