Very reliable by 1960's standards an era when a motorcycle that had traveled 20,000 miles was marveled at. They produce a marginal spark with original components especially for starting. Like RD says all new components, the points assemblies wear out making them even MORE erratic than they were new, the coils weren't much more than feeble when new.
Where I am headed; if you want a hop on, hit the button and go bike an electronic ignition will cost in the same neighborhood as all new points stuff and be much more accurate, especially if you go with electronic advance. Yes I have and run both on XS650's The difference in timing accuracy (seen with a timing light) is "significant". Spark strength at kick over speed with the starter dragging down the battery? Guess which I prefer?