I use oceanic diaphragm first stages... The older kind, DX2 I think is the model designation. They are work horses, been to 200' with not even a hiccup. I use an alpha sp4 piston reg on one of my deco bottles and one for playing around on the beach and never had any problems. I will also admit that I used an alpha piston reg for salt water beach dives for three or four years with out any service (just rinising after the dive) and it still kept on going. when I had it serviced ( the filter got water in it) the tech said the inside looked like it was serviced a year ao with almost no wear on it.
The SP4 reg isn't a deep water reg, more suited to shallow water, but the DX diaphragm reg will go anywhere a human can go and perform at the top of the list with regs three times the price. service on the regs is basic and easy and parts are common to many other brands.
The delta second stage is one of the best regs you can buy at any price, and the adjustment is by far better then any other user adjustable reg out there.
go with the oceanic reg, you won't be disappointed.
I would like to see anyone who has a horror story about oceanic regs to please post it here.I know alot of people who use them and never heard anyone say a bad word about them. Even guys who abuse the hell out of them... (myself) included