I recently bought an ironman fridge and had my heart set on a 65L dual zone, I ended up getting the 50L icecube as I wanted the option to fit it in the cab and the 65/74L chest ironman freezer just wouldn't fit in the back door as it only opens a short distance.
The difference between the 65 and 74L is purely the divider, so the 65L can be used as a fridge and freezer at the same time, only certain sides can be used though so only 3 out of 4 fridge freezer options are available, I assume this is due to the location of the compressor in the unit. So the 74L is the same external dimensions just has no divider hence giving it an extra 9L capacity but has the down side of only being able to use it solely a fridge or feezer. And yes they run the larger danfoss style compressor called the BD50f.