Unfortunately I haven't stayed in the one level, so I can't compare and contrast for you. But, I can tell you that the two level was awesome. There was a huge balcony on the lower level with sliding doors from both the living area and the dining area. And there was an upper level balcony from one of the two upstairs bedrooms. That was cool because it was at the highest height possible and right in the center under the Boardwalk sign. The living room is two stories high which looks cool and so unlike a hotel room! I imagine it's pretty similar to the one level otherwise. The possible disadvantages are that the washer/dryer is upstairs and one of the bedrooms upstairs has french doors with glass panes and no curtains. The doors overook the stairway mostly. The problem with this was that if lights were on in the living/kithen/dining areas downstairs it was bright in the bedroom. Also if someone was coming up the stairs they could see into the bedroom making privacy a bit of an issue.
I imagine you've seen the layout and know that the master bedroom and bathroom are on the lower level. Something kind of weird about that is that there are two bathrooms downstairs adjacent to each other. That's good so that people hanging out downstairs can use the bathroom down there and still give the occupants of the master rights to their own private bath...except the stand alone shower is in the second bath (and no shower, just a bath in the master). I guess that's a good set-up if there are people sleeping on the sleeper sofa in the living room.