Just from MY perspective, YMMV of course. I don't have any personal experience but more friends from the 4x4 club experience so here goes.
Whytner fridges from my friends experience have been problematic, with poor customer service. One of the guys that has one is a high end refrigeration / cooling specialist, and dug into the unit, MFG issues with the control circuits, quality control issues with the electronics / soldering... Basically poor Chinese QC. No clue if it was just that specific unit. The other guy that had one had a similar experience, but kept returning it to Home Depot until they just gave him a refund. Both said Customer Service was on par with AT&T.
Alpicool. Only know 1 person with an Alpicool, and he never says a bad word about it. That's all the input I can give on there.
I currently do not own a 12v fridge, but honestly with the ask the man that owns one reviews, have been leaning heavily toward the Iceco JP50. These seem to be the most popular in the club, and the guys I know with them are NOT kind to them. Not blasting through Baja or anything, but a lot of southern whitetail trips along muddy, rocky, treefall lined trails to base camp.
For NOW, and honestly at least the next couple of years, I am going to use my Lifetime 55QT high performance cooler. I guess I just need to learn to be happy with that. It performs exactly as I expect it to, Keep it out of the direct sun, pre chill it somewhat, have the food going in good and cold first, and get / make my ice in block form, preferrably in a container, my wifes old Fuji water bottles are great for this, and we have a weeks worth of food preservation. Block ice is hard to get on the road I know. I tend to double up gallon zipper freezer bags, and divvy up bagged ice if I go beyond a week... I am nor do I plan to be before retirment, more than a week between places to get bagged ice. Heck we've gotten bagged ice in the middle of nowhere Mexico plenty of times...