I know I am going to get beat up for what I am about to say, so here goes. If I had to buy more regs than I already own, I would but a Scubapro mk 5 first stadge, and an adjustable second either in balanced or unbalanced. I can only speak for myself. At one time I owned 4, 2 for service, and 2 that served as backups. I am not going to bore you with details, but my regs have seen severe, extreme, service off the coast of Rhode Island. They may not be the best breathing, and god knows you got a hunk of metal in your mouth, but mine have never failed or skipped a beat. True this is old school technology, but they have truly stood the test of time. There are plenty of parts available, and I can say without fear of contradiction, they will take a beating. At present I own the sp a700, sp pilot, and sp mk5 balanced adjustable. Of the three, if I were called on to do something right now, I would take the mk5. I do not have enough hours on the a700 to pass judgement, and though the pilot might be the best reg ever built, I can say from experience she is very, very, tempermental. The mk5 is dependable, reliable, and durable. They can also be had for skinny money on Ebay. Have them rebuilt and you have a brand new reg.