OldSlowHans
CinC of Everything Else
We have the Whirlpool brand of stackables and they work pretty well. Occasionally, when washing towels, we'll have to run the spin/drain cycle to get excess water out of the towels but it's no big deal.
One suggestion for whichever brand you select is to have the installers run an extra length of hose for the hot and cold water between the wall and the washer. Have them install a water shutoff on each hose that you can reach. That way, if you should have a water leak behind the washer/dryer stack, you can shut off the water to the washing machine without having to shut off the water to the whole RV.
Just a thought....
What are the model name or number of your Whirlpool machines?