Up & Over sampling Is one superior to the other?

I see many contrasting ideas on up sampling, and over sampling. I want to get a DAC quite soon and have gotten the impression from reading reviews, that up sampling is a more forward presentation and can be analytical.... over sampling is more resolving and refined, yet laid back sounding.

Have I the wrong thoughts here? or is therre any truth to those diffs?

Do tubes really make significant diffs over strickly solid state (given all else is resonably the same)?

I thought to try making sure before taking the plunge.

I am most grateful for any help here from those who have had both or either...