Originally Posted by
yamcha
... internal hubs are so well made and reliable ...
I agree. And they are nice in nordic winter - at least my Merc's oiled hub gears have worked ok.
But what about this
http://www.flickr.com/photos/nc_psyclist/2262303340/ - would a front derailleur be reliable in folding-bikes. BTW I think Jur's advice is worth to remember.