Stackable, vented for us. Splendide. After figuring out it's idiosyncrasies (basically balancing a load in the washer drum) it's worked great. I tracked the water usage. A normal load takes 7 gallons of water, dumps into the bathroom grey tank, and all that laundry soap water works magnificent for backflushing into the black tank to help clean it out. So, the washing machine actually serves double duty at the expense of one use!
Of course the loads are smaller than a home unit and the dryer does take about double time from a home unit on 220 volt electricity, but if washing when the machine is full, every time, it keep up with the demand wonderfully. Besides, when caught in the rain, or after returning from swimming, it's absolutely great to throw wet clothes in the dryer immediately instead of hanging them all over the camper to air dry (or outside for the entire world to see!)
Who you are right now is a sum total off all you use to be.
2019 Montana High Country 375FL
2014 Chevy Silverado Duramax, 6.6L Dually