I read a number of on-line "Best 12 V Refigerators" as well as comparison articles.
It is my perspective that they are all comparable in price, reliability and performance but some are made of ABS plastic inside and out, some are all metal, some are plastic outside with stainless interiors, some open length wise, some open width wise, some have built in drains and all but the Engel use the Danfoss DB35 compressor. It seems that the Engel compressor consumes a little less power than the Danfoss.
The bigger refrigerators (40 L) and larger seem to have a few more variations in configuration than smaller refrigerators.
BTW: Truckfridge refrigerators are the Indel B refrigerators.
Here is an incomplete spreadsheet I put together recently for the small to mid size 12V refrigerators.
I settled on the Norcold NRF-30 primarlily due to size and weight needs but have not made the purchase yet.
I hope this is helpful
Craig