I run Stelvios on my Birdy and have got two slow leaks over the past two months from potholes that I was not able to see or avoid in time. There definitely is a trade off when running skinny, high pressure tires on small wheels. I have since been only pumping the tires to 100 in the front and 110 in the back instead of the 120 maximum. We'll see if that helps any.

In contrast, I have run over tons of stuff on my Dahon with Marathon Racers and have yet to get a flat. Speed wise, the Birdy is only slightly faster, maybe because the wheels are smaller and it is geared slightly lower? Of course, the ride on the Birdy is a lot smoother .