My set was delivered yesterday. I am taking pictures of the assembly process and so far, things look really good. Right now, I have completed 5 of the 6 bags needed for the first stage.
I thought for sure I had been sold a bill of goods based on just the first pack, but no, this thing has modeled the internal fuel tanks, as well as the outside of the rocket.
At some stages, the build get quite fragile before reinforcements are added in. Once additional parts are added, things get stable again. While the whole build is not for kids, you can certainly have your 8 year old assemble some of the components, while you perform most of the final assembly. If your kids will insist on doing it all, then I would say 12 is a minimum age, with 14+ being optimal for a person to do it entirely on their own. Some experience with Lego will be needed.
This is a kit that can be used to help foster interest in space and science. I would highly recommend this kit for anyone with an interest in space or someone who wishes to develop an interest in space.