I just did a
106 mile overnight trip -- with camping gear -- with my Swift, including 80 miles the first day. Without the camping gear the same effort would have easily yielded a century the first day. Although in fairness, this was on flattish terrain with only rolling hills.
This was with 20x1.95 (406mm) BMX tires, a semislick in back and a somewhat knobby tire in front, at 90-100 psi. I believe that with these tires my Swift is about as fast as my cyclocross bike with 700x32 semislicks. Perhaps a bit slower than a racing bike, but then again I don't have any interest in racing bikes. Presumably skinnier slicks on the Swift would have been faster, especially on 451mm rims (though switching to 451s is a non-trivial thing to do).
The Swift (at least the Xootr version) could more or less be seen as a budget Bike Friday. "Performance that packs", but at a lower price.
As for gearing, I've replaced the standard 11-28 cassette with an 11-34, yielding a gear inch range of about 28 to 87 inches. This goes a tad lower than the lowest gear on a normal road triple (even one with a 12-27 cassette), and on the high end is still tall enough to allow comfortable pedaling up to about 30mph. On downhills beyond 30mph I rarely find it necessary to pedal anyway, so I consider the gearing "just right." Put another way, an 11-34 gives you a slightly wider gear range than the BOTH the small and middle chainrings of a typical racing bike, but without the need to shift the front. Nicely spaced gear steps too, with none larger than 15% except for a 31% jump up from the very lowest gear.