If you are staying in the 40 range - I don't think you'll have a problem with any reg. To get much below that - then go with something sealed like the Flathead VI. But the Envoy deluxe is a great breathing reg...
Here's a quote from our site:
Both the Zeagle Envoy and the Zeagle Envoy Deluxe Regulator have had Rodale's review them...Here is what they say about the Envoy Deluxe..."The Zeagle Envoy Deluxe Regulator is similar to the Envoy, with the addition of a resistance knob that enables you to tune the regulator to diving conditions. It was the only reg in it's price class to earn perfect simulator scores. The Zeagle Envoy Deluxe Regulator Work of breathing was slightly better than the Envoy... thanks to the ability to adjust for optimum performance. It's dry, a great breather, and clears easily."
Rodale's Scuba Diving, Nov. 2003:Best New Regs.