48 here. Got back into riding 2.5 yrs ago with a hybrid, and 25kms was a looooong way to go, let alone hills. Kept it up and then started riding with the local rando club. It was then where I felt the need for a roadie. Yes, a big difference in everything. Fast fwd to Apr of this year, I saw a SS advertised for $300. Well wouldn't that be a nice n+1 to have so the carbon roadie wouldn't be stolen on a short ride to the store. It soon became my bike of choice, and the hills became a little easier each and every time with the lack of bailout gears.
I spoke with a couple of FG riders on the 1200km rides this summer, and then broke loose and bought a cog. So now the bike I love to ride is the FG. Sure the downhills are far more difficult that the ups, but all in all it's a great ride and no more physically traumatic than the geared or freewheel ride.
eta: I ended up riding my SS on a 600km brevet in August and may try one this year on the FG.