-Brompton is commonly mentioned as the best folding bike. Why?
The original design was developed by Andrew Ritchie in the late 1970s. The mechanism has numerous small details that make the package work.
-Wheelbase is 1045mm, just like regular adult bikes. This makes Brompton a proper bicycle to ride.
-Wheels are small to make the package as small as possible when folded. To compensate the increase in rolling resistance, Brompton has tires that can be inflated to a high pressure.
-The frame has rear suspension to provide a smooth ride.
-When folded, the bike won't open on it's own. The seat post secures the whole "package" in the final stage of the fold. No separate lever is needed for this. It can easily be moved around, carried in trains etc. The nose of the standard Brompton seat is designed to form a handle for carrying the bike.
-The chain is in the middle of the bike when folded. It protects the chain and chain guide, but more importantly it prevents the chain from staining your clothes.
-Brompton doesn't need a separate kick stand. It has a parking position.
-With the Eazy Wheels Brompton can also be used as a wheeled bag.

Other questions we have had:
-The rear tire looks to be asymmetric in the rear triagle. Is this right?
Yes. The rear triangle is asymmetric to create sufficient space for the front chain ring when folded. To compensate for this, the bottom tube on the right side has a small pocket to avoid tire rub. The rear tire is aligned with the main frame.
-My chain sometimes slips when there is snow. Why?
This is caused by snow sticking beside the rear sprocket. We have never had problems with freewheel freezing. Lubing won't help because the packed snow just lifts the chain from the teeth. Only remedy is to keep the side of the sprocket free of snow with a stick or a toothbrush etc.
You can also change the rear sprocket to a slightly taller one (bigger sprocket is less prone to pack up with snow). N.B. Doing this has naturally an effect on gearing also.