I have used both types of valves. I like the automatic valves but I do not like the reduced exhaust flow I have experienced in all of them so far. I think that you should get an environmentally sealed reg for the waters you will be diving in. (Most manufactures recommend an environmental kit for diving in waters below 52 degrees F) I use environmentally sealed regs for all of my diving, since I dive in cold water, (34 -52 degrees F), when I'm deep, all year long. I do not believe you will ever freeze a Sherwood, (and models above the Brut or Magnum level), or a Zeagle. In the UK, the Apeks are practically the same as a Zeagle and should offer you ease of service and parts procurement, when needed. Good luck on your choices!