They're very popular now and making a good name for themselves. I run them on the track MX5 and I've sold a lot of sets to DC2, EK9, Celica, Evo and other marques and as yet had nothing but good things said about them.
You're looking in the region of £115 for a set of rear EBC ultimax yes? (quick google search)
A set of the same MTEC discs will cost you around £60 (delivered).
Are the EBC twice as good? Will they last twice as long? They'd have to, to justify the cost
I've run EBC, Black Diamond, Apec, AP Racing, Wilwood, Blueprint and Dephi discs, and for the price, the MTEC discs take some beating. Especially as they cost the same either plain, grooved, drilled or any combination of the above. They can even do curved grooved if you like.