It is a mistery for me too, Andy, but you just need a very quick google research to find out how many people spent that money and is extremely happy of their purchase.
If people have sync problems and they buy a 700/800 euro sync device and it does not solve their problem I am sure the web would be full of complains and posts about fraud etc.
I unfortunately was not able to understand exactly how do they do what they do.
In innerclock system page, you will find anyway, I think, quite a lot of info which you probably will be more able than me in understanding.
Then, once you understand, I would be glad if you explain it to me!
Even if, till David will not confirm that the sync problems between Octatrack and Ableton can be solved with his product, I will not buy it.
Ser