Sorry to rehash an old thread but looking for some new accessories for my Matrix before summer, I came across this, I thought I'd reply.
The Matrix is an awesome hot tub. Its isn't a self cleaning hot tub its a self sanitising hot tub.
There are self cleaning hot tubs on the market but from what I could gather self cleaning means "hot tub has filter system". Of course all hot tubs have this so marketing it as a special feature is a little bold. The self sanitising hot tubs from the hot tub superstore seem to be the only ones in the UK and the prices are good too.
I'm sure the OP has already chosen a hot tub but for what its worth and perhaps any future readers the hot tub superstore has been a great experience for me. No extra charges for delivery and install etc and straight to the point advice every step of the way and the self sanitising seems to be great.