the big one: how do you choose speakers? By what features, data?

I don't consider myself an expert, but to me the overwhelmingly most significant criteria are how they sound and work in my room.  Price is always a consideration, but the specs, brands, design, etc., mean little in comparison to their sound. 

Probably none you list, at least for me.  It's only based on the outcome of listening, and using music I am familiar with that I play at home.  Of course price is always a factor.

@knotscott @rpeluso so that means you need to demo it at home or at the dealer? Do you narrow down your list based on something(s) for what you would demo?

Sound only and obviously with your current equipment ss or tube will play a role