you'll have fun with the honda, it looks good in the picture. You'll still need to learn a few skills beyond "lawn mower basic" but the interweb is full of help and the parts are almost all available somewhere. they built millions of those so every known concern and fix are well documented.
Norton is not the unreliable grenade that they have the reputation for in most circles. They have quirks, so did all the motorcycles of that era. The British engineers that could build GP cars and aircraft to rival the world just didn't have the money to keep the industry afloat. Just dont buy into vintage thinking I can tinker and ride when i want and it cant be that expensive. It's fun and affordable (sort of) but its not cheap and its not for everybody. Gauge what you think you can afford, triple it, then set aside a few more bucks for stuff you never dreamt of.