Originally Posted by dty
do they generally stuff up more than regular bikes like with more moving pieces and the constant opening and shutting?
Depends on the model.
Dahons definitely fail more than regular bikes -- enough that a mechanic I know derides them as "bike-shaped objects" (while regarding Bike Friday as a "real" bike). Most of the failures are in the handlepost, which are very flexy and can eventually crack / break if you pull back on them, e.g. standing in the saddle, climbing etc.
Also, you do have to make sure that the hinges on the Dahons are at the right tension. Even if you use Loc-Tite, they can loosen up a little bit as you fold / unfold it.
However, even with the Dahons, as long as you don't pull back on the bars constantly and add one action to your regular maintenance (namely, check the hinges) the extra maintenance can be minimal.
Other designs, like Bike Friday, Brompton, Swift etc should not have issues like this. Not sure about other manufacturers.