I have a Dometic 28L, that I've been running basically 24/7 since 2016. Other than the compressor being a little louder than it was when brand new, it runs flawlessly.
Size-wise... I'm a solo traveler, so I only carry supplies for myself. Typically I carry all my lunch supplies during the week, and will just stuff in extra things for trips. I always think I want more room, but I always come back from trips with a fair amount of untouched food and drinks. I try to keep it fairly full at all times with drinks, food, and even dry goods that don't need the cold because I know fridges are a bit more efficient when full.
Power-wise... I've had mine plugged into a factory rear power jack in my Jeep. So no extra battery. I've also been running it on the lowest shut-off setting because it will go into a "power save" cycle very quickly once the Jeep is shut off. (less than 4-6 hours) Because of this, it has "softened" the battery over time. I can tell it does not have the cold cranking ability it had when new (I'm a mechanic, and I know this is terrible for the battery).... But It's currently still functional. (I also have a "donor" battery in my second jeep, that I've swapped from time to time)
A while back, I bought a Yeti 1000. With it, and the optional regulated power cord from Yeti, (read up on the voltage drop problem with the lithium Yeti's) I found I can run the fridge for 4 or more days on a single charge. Just in the last week I finally mounted my Renogy 100w Eclipse solar panel, with a simple pair of wires + an 8mm plug adapter, to feed the Yeti some sun. So far I'm really impressed with how well the system stays topped up. It's winter, so it's not very warm outside right now, but my vehicle also goes into shade around 2pm. So that it's still staying topped up enough to not need the regulated power cord is impressive.
Would I buy it again? Absolutley! I bought it at Overland Expo West as a show deal. On my multi-week trip to to the show, I hit the limits of my cooler fairly early (90 degree days). So when I came across the Dometic booth at the show, I was sold. At the time the only well known option was the ARB 50 which was WAY more than I would need, or wanted to fit into my Jeep. So when I saw the size of my 28L, I bought the only US model they had there! HA! The only thing I would honestly like to change about it, is that I would REALLY like a side opening top over the hinge being at the end.