Also depends on the attendees' heights. If on the short side, mezzanine definitely. The little slope helps greatly.
I have seen MR three times, once from tenth or eleventh row center; once from row S on the side; once from front mezzanine, I think Row E two seats off the aisle, but side. I loved the show all three times. I felt, however, that the mezzanine was best, partially because I had no issue with heads in front of me, partially because I personally always think dancing looks better from the mezzanine, partially because I think it provided the most sweeping views of the stage.
I will say that I am 5'11" (shrunk from 6'1"
, and had to move constantly to see around the tall fidgety person in front of me when I had the 10th or 11th row of the orchestra. Less risk in the front mezzanine.
I have not seen WSS, but will admit that I bought in the orchestra, only because I was trying to keep costs down, and am gambling that my $79 tickets in M19 will be acceptable. Since there are 6 or 7 seats further to the side, for most shows this would be a fine seat. Not sure re WSS, based on the comments, but seat M17 was $159, so I figured that I got a great deal. We shall see. Had it not been for my cheap streak, I would have gotten front mezzanine, although I do feel that the front mezzanine seems very far from the stage in that particular theatre. I do believe the dancing -- based solely on part experience -- would be better served, however.