Not to overload you with information, but I'll just mention a few more things . . .
I, too, liked the idea of the NS better, so I bought that one first. Then, I saw a lot of people here saying how great the FS was, especially for taller folks, and being impressed with the NS, I purchased an FS for a great price on Ebay. I ended up getting both bikes for the price that I was originally going to spend on a mid-range Dahon.
After riding both, the FS was the clear choice for me - more comfortable and stable for my size. So as you said, "you can't ride an idea" and my idea that the NS was better flew out the window. (My partner, who's 5'9", loves the NS...)
The 20" wheels will feel strange at first, but they are oddly addictive. I presently own 3 other bikes, a high end mountain bike, good road/touring bike (did a metric century on it this weekend), and a commuting bike (in it's former life it was a Fat Chance Yo Eddy, an awesome mountain bike). But I am always most excited to get back on the folder...
Morgan