I think that the best reg for you place with thewonderful combination of salt and cold, is apeks. I amnot to sure about the US dollar prices, but the ATX50 i not too bad. It is environmentally sealed and will outperform you! Even if the ATX50 is a little steep ask for the ATX40. The same thing without the Adjustment feature. Not to necessary unless you are diving deeper. You would like the apeks.
However, as mentioned check out what is available in your area, and see what you are able to get serviced. If anything I would recommend keeping away from open port pistons. First of all the salt (unless you are among the very few that rinse and rinse and rinse) and secondly the cold water. I don't know when you cut off your dive season, but freeze-ups are not to fun. Maybe report back with what is available in your area and you will get a little more narowed down opinion.