I ride a Reise & Mueller Birdy Mk3 mostly because I think folding bikes are neat and the Birdy has my favorite fold. The other rationale was that I wanted a nice bike I'd never have to lock up outside in NYC. The intention was to use it as a commuter since not spending on the subway would pay for it pretty quickly but shortly after I got it I started working remote so I've only done commutes on it for a couple weeks of gig jobs and it's mostly a recreational bike.

I went through an extended project to make it faster and wound up with a loop handlebar for body position, replaced the wheelset to move from 355 to 406 for tire selection and did the drivetrain at the same time to accommodate a 9-32 cassette. Between the wheels and the sub-11 tooth sprockets I can pedal up to ~26mph instead of ~20mph on the stock setup (good enough) and the low end is about the same. It doesn't perform like a race bike but it's pretty close to an endurance road bike. I do 20 mile rides a couple times a week on it and I've done a couple centuries.

The Birdy is my main bike but I'm a folding and recumbent enthusiast in general. The addition of the fold or moving the cranks in front of the rider means the obvious solution diamond frame doesn't work and I like seeing the creativity of the solutions. I've also owned a Xootr Swift that I gave away to my nephews, a Bike Friday Sat-R-Day folding recumbent for riding slowly in the parks, and a Baron Optima lowracer recumbent that I prefer for rides over 90 minutes.