Got this for my 5-year-old, who likes technical stuff. Wasn't sure how it would go, since the age guide is 8+.
He really liked it, and it provided some quality father-son time. It didn't attempt to be too whizzy and didn't over-promise.
We made a kaleidescope, periscope, camera obscura, and linked some LEDs to a 9V battery via a circuit board. We learned about how light bounces off mirrors, how it's bent by lenses, how a circuit has to be connected, and how blue, green and red LEDs make a white light.
There are a few conjouring trick type pieces - a two-way mirror, a piece of plastic with a ridged surface that coins seem to sink into, and some shadow puppets.
Everything was good quality, safe to work with, and managable. The only bit that didn't work was the optical fibre - not sure why, but will try cutting the ends more cleanly. Only additional item needed was the battery.
The lad asked to get it out several times over about 3 weeks. I think we've probably exhausted it now, and it will probably go in a cupboard soon, but for the price, we got a lot of fun and some relaxed easy learning out of it.