I'm not DIR, I have never taken any GUE class. I was a big Poseidon fan for many years. Then, I started using Apeks. Around the same time, Poseidon was having trouble with their US distributor. For a few years, I couldnt get parts. When I really needed them, I found them, however, they were extremely overpriced. This ticked me off about Poseidon. Then, I had issues with HP seats, and went thru a few to get one that actually held at a stable IP. SO, you might say that I was irritated. I didnt let this get to me. I stuck with my Poseidons. Then, as I using the Apeks regs for teaching, I found they were very nice. Overhauling them was easy, parts were very easy to come by. I started thinking to myself... Hmmmm.... This seems like a much better way to go. SO, you know what I did? I sold all four of my Poseidons. Yeah, the parts issues have been solved now, with Viking taking over the distribution of them. Yeah, the prices on parts have come down on Poseidon. But, you know what, I just didnt like them anymore. The ease of servicing the Apeks regs, the effortless breathing (no more sttuterring from my Odin), all convinced me to go Apeks. I now own five of them...
Now, this could have happened with a Scubapro reg, but I doubt it, because I dive in cold water alot, and I actually like the environmental seal of the APeks regs for cold water. They work well in cold water. Scubapro, ehhh... You never know. It might freeflow, it might not. So, thats that story.
Dive Rite regs. Well, I have never tried one. Maybe if I do, I might like them. Right now, Im sticking with Apeks. They have been making regs for a LONG time. Dive Rite has not. Dive Rite doesnt make these regs. Thats another concern.
Zeagle... I dont like the cheap plastics they use for the second stage. Seen a few crack. Yeah, they were recalled, and they took care of it, but it never set right with me. Also, the design and overall looks of the reg dont quite look that good to me. They look like a fisher price play regulator. Thats why I dont like Zeagle.
The insides of the regs. Ive seen all of the above, and I like the APeks better.
To each his own. Let everyone decide for themselves what they want to dive. There is a reason why APeks is well liked here, and around the diving community: Its a great reg. There are many other choices, but I chose Apeks for the above reasons...