This is an excellent set for this price. I didn't want to spend too much just in case my kids didn't really take to it, but most other sub-£40 sets are battery operated and I specifically wanted mains powered which this is. I actually found it elsewhere for £25 which was a bargain !
The cars are quick and a magnet secures them to the track (although they will come off after a long straight at full speed. The track itself took a while to set up but I've had no problems with it coming apart due to the clips which hold each piece together. The brushes are fine so far after 3/4 days of heavy use.
The only problem is 3 out of 4 wing-mirrors have broken off, and the crash barriers don't really serve any purpose as the cars go over them. I've decided not to fit them which cuts down the time to set it up.
Anyway, the kids love it and I'm now looking to by one of the extension packs.