Well, I took it for its first run today (bar 200 yards up and down the road last night in the dark). To test the hub, I used the alternative commute which involves going straight up a rather steep hill from my house, not far short of 1:7 near the top. No wind at all, so my impressions couldn't be confused by a headwind (I'm going well) or tailwind (this bike is too slow).
It rolls incredibly well on the flat, much better than the Thorn, but you'd expect that with 700c racing tyres. It felt a tad undergeared on 60", but given the huge drop to low gear, that's OK - when there is a headwind, shifting down is a last resort. The hub is faultless, with no slip in low or normal gears (the two you can stand up in). 45" was fine for getting up the steep hill and 80" is useful downhill to avoid spinning out too fast. There was a pleasing absence of rattles due to the tight chain and pretty generous mudguard clearances most of the way round [1]. No axle creep - those serrated washers do the job.
The bars will take a bit of getting used to because they're narrower at the hoods. The stem probably needs to go down half an inch too. Steering is neutral in the sense that I didn't notice it at all. It's not a floppy as the Thorn but not as stiff as a racing bike. The ride is very comfortable - high TPI, skinwall racing tyres at 120psi are much better than low TPI touring tyres at 90psi.
One small problem - rear brake rub when out of the saddle, caused when pushing on the LH crank. Dual-pivot brakes, pencil stays and the need for a tiny amount of play in Sturmey hub bearings [2] all contribute. I screwed the cable adjuster in which got rid of most of it, and I think the brake could be centred slightly better. You may have noticed that the pros climb mountains with the rear brake QR undone, and they're on super-stiff carbon frames.
[1] I have a spare 17T sprocket which would raise the gearing to 63.5", but the 1/8" of resulting axle movement would put the tyre perilously close to the mudguard under the rear reflector - the bottom rear stays (untrimmed) are only just long enough as is, because of the 50s-style mudguard eye halfway up the seatstay. P-clips are an option if I really need to gear up.
[2] if there is no play at all, the cranks have a tendency to rotate when freewheeling. I remember this happening on my old Chopper.