Well I've taken the plunge now and have gone with an engel 40 lt steel body model. Got a decent price at BCF, I spent ages comparing with the waeco models. I did find that there were some features about the waeco that I liked more than the engel, but with things like plastic catches on the waeco, vs steel catches on the engel, integrated temp display, steel body vs plastic and the things I've been told about engel reliability, I had to go with the engel. Interestingly, the quoted power consumption on the waeco was lower than the engel.
If I had the budget I'd get a cfx50 as well and compare them side by side, but can't do it, I need the coin for a suspension lift...