Waecos are what the newer DanFoss compressor-based fridges were designed after. They had been in service all over Austrailia for a few years before ARB caught up. And good for ARB to use such an effective design!
Dometic has bought Waeco and now sell the fridge under their badge (recent design has digital temp controls, more low voltage cutoff settings, etc).
They are significantly cheaper than ARBs for what amounts to the same design...
(both AC/DC models)
Dometic CF-50 $605 transit/insulating bag $50
vs
ARB 50QT $800 transit/insulating bag $175
Would recommend either as well as the Luna and others.
The size of fridge and using an insulating bag, along with keeping the fridge full, are key to saving energy. I don't recall if a study was ever done of the difference between a bag vs without. There seems to be a lot of anecdotes about power usage. Mine is that I have gone 3 days without charging leaving the fridge running on a single battery, then started up the truck and drove away. I think I had a wool blanket over it as well. An aux battery is sensible but not a necessity unless you are in hot environments or long stays.
Whatever you end up with, I doubt you'll be disappointed!