I'm Rich, 52, I have a 'bent (Rans Rocket) and a folder (Montague CX). I've also ordered another folder, a Dahon Helios SL.
I alternate between the 'bent and the Montague every other day, usually easy cruising on the Rocket, "hard day" on the Montague, which I use on the road and non-technical off-road. The Montague's a nice sturdy bike but it's a bit heavy and slow (fat tires) and doesn't fold too compactly for use on transit. The Dahon is for going faster, road only, and for taking on transit (our local light rail in San Jose, CA). I have been known to go faster on the Rocket on club rides, and I've even used it in time trials.
Some days I also ride the Montague to town where I meet my wife and bum a ride home with her, so it's good to be able to pitch it in the trunk. You have to take the front wheel off the Montague to do this, so it'll be easier when I get the dahon