No question about it being suitable for 10k, after 40k on city streets and the road vibration from the size of the wheels starts to get you down (longest ride I think was about 60Km). FTR, I'm between 90-100kg, I put a Brooks on it. The handling is really quite nice, it comes with ergo grips and the steering and castor angle is good. I run it on slicks (Kojak, I think) and the combination of grip and roll is good, too.
Here's what I've learned over the years:
Great benefits from regular checkup and adjustment of all the latching mechanisms.
The safety latch on the main fold lock gets knocked off easy, no real issue as a result.
Despite looking complicated "servicing" (ie greasing) the coaster hub is easy.
A slight notch filed in the seatpost that can be located with a fingernail helps fast adjustment
The seatpost (and your hand you use to find the notch ^^) will get dirty
The original wheels pinged a large number of spokes for the first few months, then stopped. Duff spokes suspected.
Make sure your repair kit includes an 8mm and 15mm spanner for rear wheel removal, the seatpost (of the dahon, anyhow) incorporates a pump.
Coaster brakes are great in town, except when you find your feet at "12 & 6"...... then you'll be grateful for the front brake!
Here's what it looked like new