Dean,
I saw it at W10 and had to have it. (wanted to go toW12 but its a long way and I didn't have time)
Yes it was an arm and a leg and the fittings must be about 80p each or something. But when I build large stuff it is absolutely indispensible. Take it all as a flat pack, fit it together and a quarter turn of an allen key. Lines everything up perfectly and clamps it tight. Sometimes I've even used them just to avoid glue up and clamping ( and it is easier to use than the Domino)
If ever you have to do big units that need assembling on site it is as big a game changer as the Domino.
So far I have never found the small holes a problem, you can usually arrange them so that they are not visible.
The guide is better than on the samll domi - I haven't got the big one yet.
Richard