I got a SS last year as a cheap bike to attend a social ride I like to participate in. Since doing so, I probably haven't ridden my Roubaix 20 miles.
The simplicity and ruggedness of the bike, coupled with some wide tires gives me a feeling like I did romping around on a BMX as a kid. It took me a minute to get used to not having bail out gears, and I still have to walk from time to time (not in a while)...but I also changed the ring and freewheel to give very low inches.