Not bad looking bikes. I would be interested to know how reliable they are and how they age.
There isn’t an awful lot to go wrong with them, like Andy says some of the electricals will need looking at but even a re-wire isn’t a huge deal. They’ve had a large following for half a century so there is loads out there for them.
There also seems to be a reasonable amount for sale over here and not for silly money. The ones priced sensibly sell quickly and the chancers have been for sale for months.
I am fond of parallel twins, I’d ideally like something air cooled, simple and with lots of aftermarket options so it’s an obvious candidate.
The one I saw was probably too nice, really, and a Special would be a better starting point for what I want to do.