I believe all dive-rite regs are made by Ocean Diver's Supply:
ODS
who also make regs marketed under the names ScubaMax, TDL, Salvo, and a few others, typically less expensive than the dive-rite versions.
I have heard a dive-rite spokesperson say that they provide (or install) some of the internal parts and do further testing, which is why the cost is higher.
In any case, this is one of the most common regulator designs in the world and you should have no trouble finding parts, either for a technician to use, or to service them yourself. Likewise with service manuals.
Personally, I have the ScubaMax version and like them just fine for recreational dives (which is all I do). I've used them in water as cold as 3C without problems. If you're following GUE gas guidelines these should breathe fine at any depth thanks the helium.
Good luck,
Pat