I sailed as a "solo" because my wife simply isn't interested in large ships (we've sailed together nine times on Silversea, Seabourn, and HAL). The price was right, and so was the length of the cruise---I figured that even if the cruise was terrible I could tolerate it for four nights).
Well, the cruise wasn't terrible. In fact, it was pretty good overall and very good in certain areas.
A nicely-designed, bright cabin, perfectly adequate for one person for even a long cruise (although pretty tight for two for anything longer than seven days). Very small bathroom, but that's par for the course.