Have raced with MTB tubulars for around a year now in Australia, but they were with the original GEAX tubular tyres, and with a 120tpi they felt awful (not much to gain on trail feedback). They have now upped the TPI to 200+ which would help, the Dugast are 'it and a bit' and I know the price in Australia for these tyres is around 120-130 pounds each, so was hoping to track them down over here.
I have got the latest Ambrosio MTB Tubular rims, so want the fancy tyres for a fancy build up.
Geax have just introduced a 'basic' training MTB tubular, which means that should a puncture happen, there are cheaper options.
In my experiance, I was getting the same amount of wear out of a tubular tyre as I was a tubeless tyre, but more care was needed. I also put aqua-seal on teh sidewalls which helped alot.