This gets discussed a lot. You might want to do a search. In fact there is an ongoing discussion about the pros and cons of an onboard w/d on one of the forums right now (don't recall which one).
I have the Splendide stackables. Being a single, this might be overkill because I could probably get along just fine with the single combo unit. But for 2 people I would definitely recommend getting the stackable separates just because of the smaller capacity.
I agree with everything Jtrac says. My dirty laundry is 2 ft away from the w/d and the closet is about the same distance so it only takes a minute to load the washer or put away clean laundry. The dryer takes about an hour to dry a load(120 volt,) but it doesn't matter because I'm not around waiting for it to get done.
I have a 35 ft rig. They do wash and dry very well, just like your home w/d, just smaller loads.
Tim