Make a move already.
I agree. It sounds like Marshall is still a year or more away from releasing anything. I am sure Garmin knows what Marshall is doing and is working on improvements. I would not doubt if they are working on and testing a collar more advanced than the dc40.
Garmin has a hell of a bigger budget for R&D than Marshall. They will take what is good for the Marshall unit and copy and intergrate it in there unit.