In my experience to #1, the complement of tubes do matter greatly, as do quality of the power supplies and especially, the quality of the output transformers.
With regard to #2, no one NOS manufacturer had a corner across the models or build configurations in terms of quality or durability. Some brands seem to be preferred over others generally, but depending on the vintage and place of manufacture, some Holland made were stellar and some were mediocre, and some German or British made tubes had mixed attributes and results, as did the US versions.
I do feel that we'll designed circuits, components and power supplies are at least as important as the best tubes put into service.
With regard to #2, no one NOS manufacturer had a corner across the models or build configurations in terms of quality or durability. Some brands seem to be preferred over others generally, but depending on the vintage and place of manufacture, some Holland made were stellar and some were mediocre, and some German or British made tubes had mixed attributes and results, as did the US versions.
I do feel that we'll designed circuits, components and power supplies are at least as important as the best tubes put into service.