The bike was quite happy to easily keep up with urban & suburban traffic, and I chose 50 on the country roads because it suited the conditions and how the bike felt at the time. Ultimately the bike is still the heavyweight single designed for pre- and just post-war British roads under the skin. Adolf may well have had autobahns at the time the original Bullets were designed, but we didn't get them for another couple of decades. I found that my Bullets were happiest on single carrigway A roads and B roads - the "roads less travelled" - and the current incarnation felt similar in that regard. If I want a faster bike I have the Interceptor - the Bullet was much more relaxing. Riding the Interceptor at similar speeds is not the same experience & neither is my MZ TS250/1, which will also cruise comfortably at 60.
I do think it is a better bike than the 4 speed bikes GR. All the "stuff" that was available to resolve issues with the older bikes appear to have been incorporated into the design of the UCE - hydraulic valve lifters, adjustable cam spindle, automatic decompressor, gear driven trochoidal oil pump & wet sump, 5 speed box are all positive improvements from my POV. Electronic ignition & EFI probably forced upon them by ever tightening emissions regs, but they still make for a more civilised, easier to live with bike than the earlier versions, which required constant "tinkering" to keep them running sweetly. And I find these days I would rather ride than tinker !
The speedo was steady at all speeds, Andy.
Price varies according to the particular model, Will, but they are not bargain prices like the Interceptors. The basic model is around £4K, rising to (IIRC) £4600 for the Classic Chrome that I tested. There maybe OTR charges to add to that, though prices are always negotiable to some extent.
Traffic conditions must be different where you live, backofbeyond. Traffic speeds around here (West Yorks) have been reducing for years, mainly due to ever reduced speed limits and increased traffic volumes. Most formerly de-restricted roads now have 40 or 50 limits, many habited areas are now getting extensive 20 limits. It is getting to the point that it now takes me an hour or more to get out the ever-widening urban sprawl to find the more interesting roads - and they mostly have restrictions. And you really don't want to push those limits, particularly in North Yorks where there are no fixed cameras but they have the largest fleet of camera vans in the country - I can all but guarantee to come across at least one on every ride there. Much the same abroad, too - lower limits tightly enforced - and it will doubtless get worse.