We got my 8 year old son a couple Sluban sets for christmas, this being the largest one. Overall, they are nice when compared to Legos, they fit together with Lego pieces and the figures actually have a larger range of motion. However, the instructions for assembling the sets are a bit lacking. If you are used to Legos, and the way they do things, then you are going to find you need to pay better attention to the directions here. Unlike Legos, the pieces more or less randomly packaged in three or four bags, no organized numbered bags here. So, the first step in assembly is to sort all the pieces by type so they are easier to find when needed. Secondly, the directions don't always make it really clear what is added at each step, which makes it easy to miss something. My 8 year-old, who is a Lego fanantic and has assembled many large Lego sets, had to ask me to put this one together for him because he couldn't get the hang of it. Granted, I believe part of that was he had gotten a lot of other Lego-type stuff and he was getting a case of assembly burn-out, but even I had to backtrack a couple times because I missed something in a previous step.
So, these are a fun, if slightly less detailed, version of Legos. Just be prepared to help younger builders put them together.