I'm thinking about getting it for my 12 year old daughter, she currently has a 66-16 I gave her, but I think she'd like the sphinx model a little more, at least aesthetically. Not sure what she'd think about losing the reverse feature.
I sew on my 27 treadle without reverse and it's fine, but if you want to chug through a quick project it's nice to be able to backtrack real quick.