It is so good that there are 'glass half-full' people like you Richard. Having lived both sides of the pond, I'm not sure about the intrinsic qualities of either of our English speaking races! I think on balance I may fall for the blandishments of our friends your side more easily than our friends this. It's your charm, you know. Even on a mind-break!
Personally, I think the important things when looking at 'buys' are these:
1. if you want a machine that is per original spec for its year, pay serious attention to the tinware, the fittings and fixtures and colours and chrome, wheels, forks and brakes and be sure to have done your homework re frame and engine numbers. Has it got the brakes it should have, the right carb, the right instruments, the right bars and levers in the right combinations, stands, whatever whatever? Are all the little bits there? How much of it is pattern parts, or worse still plastic? The small parts are often the hardest to find - eg air filter parts, correct headlamp ears, etc etc.
I say at once that this largely excludes me as I have no idea what goes with what in terms of chronology or what colour it should be. But I know these things can cost money to sort out if they are wrong and the info is all out there, or here, or somewhere. All sellers make light of these things, of course . . .
2. if, on top of the right bits in the right places, you want working mechanicals and electrics etc, then I have to say I believe we're in lottery territory if it's not a known bike. It might be great, it might be horrible. If it starts and runs and makes no horrible noises, it could be fine for years . . . or days. Or minutes. While I'm happy to run stuff 'as bought' - if it runs at all - I always expect to have to pull the oily bits apart sooner rather than later. For most of us with As - I exclude variants with funny strokes, special parts or other sorts of unobtainium - the basic bits are actually available and cheap. If originality is important, far better to buy a correct machine with the right mix of bits but with honestly-tired mechanicals than to do the other thing. Although we focus on them here a lot, the oily bits are the cheap ones. Maybe that's why I like them . . . .
My problem, of course, is that I don't really give a stuff about the shiny bits, nor for 'originality' in all things. I always fall for things that run right and handle right (for a day at least!) and can be made into mile-eaters that don't break down too often. Natch, it's a bonus if they look semi-right too.
However, the difference between the things that I have and the better things a lot of people prefer to own can be a lot of $$$, £££ or Euros. Good 'oily rag' is, though, often better than 'shiny but shame about the trailer'.