I just picked up a second-hand curve SL (the older IGH model) so I'll be putting it through it's paces. It's taken a lot of servicing to get it running properly but first impressions are very favorable. Weird as I was riding a Curve D3 a while back and found it significantly harsher than my 20" Dahon, but I'm not getting that with this model; it's surprisingly smooth-riding. Potholes do look scarier though.