I have used this Excellent Atomic M1 Regulator for the last 2 years as my back up regulator. Used it as my primary on 5 Dives in Portland a couple of weeks ago and it performed well. Not needed now due to a change in circumstances. It was serviced by Dive Manchester under 2 years ago so still in service. The only issue on the regulator is a small split in the purge membrane cover which in no way affects its performance but I assume you would get it replaced at the next service. If you are looking you know the quality of Atomic regulators. This was 800 when new and of course once serviced they are as good as new. I always look after my equipment and ensure they are well cleaned following use.
Any questions feel free to ask.