The flip side of the Quest's flat floor is that said flat floor is at least a foot higher than the slightly bumpy floor of the fold-into-the-floor competitors. Check out the total cargo volume stats, for instance: the Quest gets pummeled.
That said, I like the Quest myself having test driven both it and the modern Chrysler Town and Country. Its interior is very nice, the powertrain smooth, and it's different from the herd.