I've used my Bike Friday NWT on 4 different short tours -- once pulling the suitcase trailer, and the other times using panniers. The only issues I have with the NWT are slightly quicker steering due to the smaller wheels (and you rapidly get used to that), and the fact that it has no top tube, so I can't just brace the bike with my thigh.
I've also used S&S coupled bikes on a number of short tours, and been perfectly happy with that. I slightly prefer the full-size bike to the Bike Friday, but if it were just for a weekend, the ease of use for the Bike Friday would definitely win.
It's definitely faster to set up or pack the Bike Friday, and both solutions allow me to transport the bike in a small car or a cab, which shouldn't work with a non-coupled full-size bike.