While I have not had an Engel, nor a Dometic, I have had a Norcold which used the same Sawafuji compressor as the Engel, and it did bother me at night, especially when I was on the verge of achieving sleep. I went through rather extreme efforts to isolate the upright front loader fridge from its cabinet in an attempt to reduce noise and vibrations.
I now have Vitrifrigo which uses a Danfoss compressor, and the Dometic's Waeco compressor appears to be a clone of the Danfoss, and my Danfoss is significantly quieter than the Sawafuji.
Also the design of the upright front loader VF fridge allowed me to employ more effective extra insulation and better condenser ventilation. My VF is an estimated 15% more efficient holding 32.5f average interior temperature compared to the 39f average temps I held on the Sawafuji powered Norcold.
As to Noise reports from Sawafuji compressors, it appears some are much quieter than others, and the hearing ability of some people is obviously different to that of others. Some here report thier sawafuji compressor based fridge is whisper quiet. Mine most certainly was NOT.
My experience with a sawafuji compressor led to many knuckle dents in the fridge door, and much time and effort was expended into quietening it down/ isolating it from cabinet and isolating compressor from fridge body. While its failure at 5 years was not a happy occurrence and might be partially attibuted to knuckle dents and the attempts at noise reduction, the replacement fridge with a Danfoss compressor is a much better performer, and much much quieter, and I will run screaming from any compressor fridge with a sawafuji compressor due to my experience with a noisy one.
My opinion from having experience both compressors, is for the noise sensitive to get a compressor fridge with a Danfoss compressor, and the least expensive offerings of such fridges appear to be the Truckfridge:
http://www.truckfridge.com/tf51.html
BUy from here for better price with free shipping:
http://www.westyventures.com/parts.html#cart_restore
I do believe the sawafuji compressor is more durable in a high vibration/ physical stress mounting location, and the reported longevity of Engel portable models in rough and tumble 4x4's is certainly good, but it did affect my sleep when there was not enought ambient white noise to drown it out. The white noise solution was more effective than basically suspending the vibrating fridge in a foam rubber noise and vibration supressing cabinet, and lining all adjacent surfaces with noise supressing materials.
Perhaps my Sawafuji was simply poorly balanced with the wrong density of rubber bushings, but Again, I will run screaming from one as its noise was in a frequency most bothersome to my ears.