All the new fridges are about the same, using the highly efficient rotary compressor. The older Engel/ARB uses the swing compressor, which is more capable in extreme environments (low voltage, high fridge operating angle etc), but is not as efficient. Here is a quick read on the rotary compressor
Bushman 12 Volt Portable Fridge Freezer for 4WD and Campling
Almost all the new models have digital temperature control.
For the sub $1000 models, there are a few as follows:
Waeco fridges are plastic and lighter, and take a beating without looking all dent up.
ARB/Engel have metal bodies. They are more durable but can be suseptible to rust and dents.
The EdgeStar is a new line of fridge that is very similar to the ARB/Engel design but at lower price.
Bushman is another line with metal bodies but also has high lid and extension to quickly change the capacity from 35l to 52l. It used to be sold in the US, but now available only in Australia.
Coleman also had a compressor fridge (34l IIRC) a while back. It is no longer available.
I had a few different fridges (and thermoelectric coolers), but now settle to a portable Waeco that I use around town. When I get my cruiser built out for full time offroad, I'll get another large (50+ L) Waeco or EdgeStar for it.