TexasMike asked me to chime in on this thread so here's my 2cents. Since the purchase has already been made, I'll change the topic a bit.
After a quick read of the thread, I've seen several regulators mentioned. Without respect to model:
Apeks
Scubapro
Zeagle
These regs. all have something in common and I'll get to that in a moment. The one thing that seems to be a major point of focusing this thread is the price. I don't know about you but when I look at my primary piece of LIFE SUPPORT equipment, $40-50 bucks one way or the other is no big deal. I care that I get the absolute best equipment I can find (notice I didn't say afford). If I can't buy it today, I'll save to get what I need. And I don't mean to imply that "most expensive is best". In todays market, that is definitely not the case! And all of the regs. mentioned are very good for recreational diving.
In my mind, to make an intelligent decision, you need to get beyond the hype, acronyms and flashy pictures in catalogs and on websites. They all look good there
heck I own a boat-load of them!
So without getting into a regulator repair class or equipment specialty let me make a long story as short as possible.
The major differences in the regs. mentioned are in the first stage. The Scubapros are of a piston design and the Apeks and Zeagles are diaphragm. Now we can argue all day on which design is better so for this discussion lets say its what works for you. The piston was actually developed from a propane regulator design many years ago. I will say that I prefer diaphragm regs. since they react to ambient pressure at depth and thus will ALWAYS breathe better at deeper depths. But if you dont dive below 100 who cares? And whats wrong with a little resistance anyway? It lets you know air(gas) is a limited quantity (consciously) so you manage it better.
The Scubabapro MK10(MK15)/G250 is one on of the most dived regulators in the world. Its been in more wrecks, caves and open ocean than most other reg.s out there. So heres where we get to the connection.
There is a guy named Jim Fox who worked for Scubapro designing the MK10-15. Now Zeagle hired him away from Scubapro in 1998 to design a new reg. for them. Well why would they want to do that? Apeks (a British company and some of the best) private labeled their regs. through Zeagle in the US. Aqua Lung/U.S. Divers bought the distribution rights from Apeks (outbid Zeagle as I understand) and now markets a redesigned Apeks reg. under the Sea Quest banner. My understanding is that there IS a difference between an actual Apeks and the Sea Quest. Ill know when I get my hands on one. Anyway, Jim Fox is the designer of the Zeagle regs. 50D and DS-4. These are basically the same regs. with the 50D having a swivel and the DS-4 sans. My preference is the DS-4
just to eliminate another potential point of failure.