I don't have any experience with a DZ refrigerator but my Engel mt45 has been flawless since I purchased it used 2 and a half years ago. I can set it well below freezing or 45 and anything in between. It lives in my van 24/7 through some wild swings of temp ranges.
What I'm getting at is, I wouldn't have any fear in purchasing a Engel refrigerator again, DZ or not.
2001 E350 PSD w/ a bunch of stuff.
And had three other E350s...