Tricky to install, but worth it!
Bought the product recently having purchased BB-8 some months ago. Me and my son (11) installed the kit together using the online instructions. I reckon it took us about an hour - and it does feel like some of the bricks don't quite "click" - which is understandable given there are now wires between Lego bricks.
Overall, the effect is brilliant and I love it now that BB-8 lights up. Will definitely buy the other light kits for my Lego collection.
Overall, great product but quite tricky to install.