I have the Apollo unit. It seems to work very well. Had the unit for a year when it started acting up. Called Blue Ox and explaned the problem. There was an air leak inside the unit. They said, no problem, they will repair it. They set me a call tag for FedEx. I set the unit to them and instead of repairing it, they sent me a brand new unit.
The new unit has been on a 1500 mile trip and so far no problems.
I think if I were to start over, I would go with the M&G system.