I don't think it's a choice between "minimum" and "viable", rather it's figuring out what the least you can ship that will still give you valuable feedback.

Typically your product will be a better alternative to an existing solution. So then "minimum viable" just means it's (slightly) better than the alternative.

If you're talking about polish, etc that's a different story. And depends on your market, who your early adopters are, and what your relationship with them is. Typically a polished design helps establish credibility, but there's many other ways to do as well.