I'll echo Larry's question on why dual voltage.... more cost, when would you ever NOT have 12V available? Most marine refrigeration is 12-24VDC as primary, the 110V capability is via a power supply that simply converts the 120V to 12/24.
I recently replaced my 2nd Vitrifrigo in less than 8yrs, I'm not a fan. Although they're pretty well made, mine were forever unreliable, and we simply were fed up with stinky milk, sticky lunch meat, and wilted produce. They simply would not maintain an adequate box temp despite extensive efforts to DX, add auxiliary ventilation, speed control, thermostat, etc. It rarely cycled off. 36 hrs to recover to 40F from defrost.
We just replaced the last VF with a NovaKool RFU9000. It's not a fit for your KK, but we love the layout, and it's been maintaining box temps of 38F pretty consistently on the mid setting. I know they have a wide range of product, they may have one to fit.
I've met several KK42 owners who had the subzero hogs, Larry's solution seems to be a happy voice in the midst.
I have a Frigoboat keel-cooled system at the heart of built-in freezer I rebuilt and converted from a holding plate, I love it. Very efficient, and absolutely silent. It can't, however be run out of the water, although they make a dual keel-cooled/air cooled condenser that can. If you do end up with Danfoss-equipped gear, and you cruise beyond easy reach of replacement parts, a spare control module would probably be a prudent addition to your parts inventory, since it seems that when a fridge/freezer with a Danfoss goes down, it's typically the control module. It's not a complicated swap-out, and having the part on board could be the difference of a temporary rise in box temps vs. total loss of the contents.
Good luck on the search, keep asking lots of questions, the questions you ask now will save you headache down the road, and there's no headache quite like a refrigeration problem on board a cruising boat!!