Both of those regs use an unbalanced piston first stage. They are utterly reliable, and have very few parts in both stages. If your dives are taking place in less than 100' of water that is warmer than 50 degrees they will work well. They will both breathe a bit harder as the tank pressure drops. This is because the intermediate pressure will lessen, so there is not as much force pushing on their second stage poppet seats. When such regs are serviced the second stage is adjusted at 3,000psi for that very same reason. If the second stage's cracking effort was set with a tank pressure of 1,000psi or less the reg would likely free flow when used with pressures over 2,500.
If you anticipate making more advanced dives in the future, I would suggest looking at a balanced piston or diaphragm first stage.
I believe that both of those regs are commonly sold on the net. I would do a search on some price checking sites. Leisure Pro would be another place to check.
Dive buddies and I have used the Mares R2 for a number of years on stage/deco bottles that are used in depths less than 100'. They are very easy for us to service and are super reliable.
If you are set on this type of reg, you might also want to look at ScubaPro's MK2 Plus regs. They are essentially the same type of unit.
Greg Barlow
