I want to know where DVC45 found a Dahon Traveller Rear Rack for "about $35" when it seems to retail online for about $80. Performance Bicycle does list one for $37, but they show an Arclite rack in the picture--and Arclites usually sell for around that price, so I'm doubtful. (NB: I did buy a Traveller Rear Rack for my new Dahon, as I wanted a rack high enough to support panniers.)
The Downtube 8H was my first folding bike. It has a nice stock gear range and solid ride but I didn't think it was particularly great as a *folding* bicycle--too heavy, clunky, and awkward, with a folded package that couldn't be balanced and needed to be leaned against something. Also, over time I grew to prefer derailleur set-ups over IGHs.
Regarding edwong3's comment that it was unfortunate I didn't know about the cheap freewheel cassette upgrade option, I *was* aware of it--thanks to him! :-) Changing the cassette wasn't going to give a high enough top end, however, without changing the front chainring. And changing the front chainring meant getting a new crankset. At that point, other bikes with higher-quality stock configurations and components started looking attractive, and I got a great deal on a 2008 Dahon Speed P8.
Truthfully, I miss the light weight and quick, easy fold of the Nova. The Dahon is heavier and the fold is fussier--you have to do more futzing with the stem and the frame hinge is stiff and effortful to fold. That said, the stock gearing is much better--I don't feel I'm running out of gears on the top end. I still wish I had a lower granny gear but it's no worse than what I had on the Nova. The gripshift is also a little strange--you turn the shift away from you ("up") to move into lower gear, whereas I'm used to the opposite configuration. Those gripes aside, I'm happy with the Dahon--it's a comfortable bike to ride right out of the box.
Overall, I think the freewheel and crankset are the Nova's Achilles' heel as they limit gearing and make upgrading expensive. It's at an attractive price point and perhaps there's a market for folks who don't need much performance out of a folding bike. Nevertheless, I think Yan should consider making a (more expensive) non-suspended derailleur bike with the same light frame as the Nova but with a freehub, replaceable chainring, and better stock gearing--it's really an option that's missing from his current product line-up.