Yes, it's ok to mix with the good stuff too.

Like a chain, a cocktail is as strong as its weakest link. Nothing is too good to mix with in my opinion. With that said, most of us have budgetary limitations, so we make do with what we can afford. Ultimately, it’s easier to mix with more modest spirits, as a great (rare or expensive) ingredient requires modifiers of equal merit. It reminds me of buying nice clothes: once you have a great pair of shoes, suddenly your pants look shabby. It can become a vicious cycle.
— Jim Meehan, from an article on Serious Eats on developing new cocktails: