The S-20 is a very pretty boat. I bet it is fun to day sail or race. Nice big roach on the mainsail, fractional rig with small jib which makes it easy to tack. The keel is very modern so I bet she goes to weather really well. There's quite a lot of overhang on both ends which gives her a very pretty appearance, but might not help performance so much. I know when she is heeled the waterline length increases, but that is old school, I believe. Most modern go fast boats have pretty plumb bows. Rule beating also has played a roll in such hull design, but if it is one design, that is moot.
Nothing like a pretty boat no matter the size and nothing like a pretty boat that sails well too.