I loved my Birdy. Never disliked it. But once I got the Brompton, it started gathering dust. With a Swift and a Moulton next to the Brompton to handle all sorts of riding, the Birdy was completely redundant.

However that doesn't help you...

Maybe if I didn't have the Moulton, I would still have the Birdy. No mistake, that is one heck of a nice folder. It was may main commuter for a long time, didn't keep count but perhaps 2 years? So I put in a major stint on it and it wasn't because I was tired of it that I sold it. Perhaps they are too close to each other... I am not in need of wide gearing so that doesn't swing it for me. I toured on the Birdy and the wider gearing was good but I have similar options ready to go on the Brommie.

So, not clear... maybe it is simply an issue of want.