My sidemount setup is Deep 6. I can't see I've been horribly deep on them at this point (130 feet only), but sidemount is my long term tec configuration. At that depth, they breath really nicely, better than my MK25 Evo/S600 setup. I haven't taken my Atomic M1's all that deep yet.
Edit: I forgot to add. Equivalent to my Apex XTX50s
Any thoughts on how the Deep6 compares to a Mk25 EVO/G260?
So the signature is nicer than the DGX?
LandonL works for Deep6, so he wants to be a bit PC. The simple answer is yes.
If you search around here (or maybe the DGX site) you can find more details on the differences between the Sig and the DGX regs.
Any/all of the regs mentioned will work fine for the things you said you want to do. 40F water is not a problem for any of them. 40F, dirty water is not going to be a problem for any of them. An unsealed, piston 1st stage may need the cap replaced every many years due to internal wear from the piston rubbing crud against the sidewalls. Mk25 EVO caps are cheap. If you give them a decent soak, particularly after diving in salt water, they shouldn't need anything but normal servicing for years and years.
If I wasn't attached to a shop, I would be ordering a pile of Deep6 Signature regs for myself right about now. As I am attached to a shop (which sells Atomic, ScubaPro, Aqualung, Apeks, Oceanic, Dive Rite, etc.), want to dive what the shop sells, and can get anything I want at VERY good prices, I am about to buy some sets of ScubaPro Mk25 EVO/G260.
BUT, one reason I would buy the Deep6 regs is because I would service them myself. Before you buy those, I would suggest to just pause for a moment and think about how you plan to get them serviced. If you will learn to service them yourself, then good to go. If you're comfortable with mailing them off for service, and confident you'll plan ahead well enough on that, then good to go.
Otherwise, you need to figure out if someone local to you will service them. Your local shop(s) may or may not be willing to work on them. If they don't have a technician that is trained on Deep6, then they may not be willing to work on them, just to protect themselves and their liability insurance. For that matter, they may not be willing to work on them just as a matter of principle, because they want you to buy regs from them, or at least buy a brand that they sell.
If you can't service them or get them serviced locally and you don't want to mail them back and forth, then Deep6 may not be the best choice for you.
