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

I prefer to buy in a store where I can listen to the speakers first and then take them home for another listen. The last ones I bought was actually used nut sold from the store with guarantee. I could even bring my amp to the store to check that they worked together. 

So, see if you have stores around you and what speakers they have. That is my advice. 

I bought my Focal Sopra 2's almost 3 years ago, when I decided to buy new speakers after owning the Celestion A1's for 22 years I did a lot of research.  I don't have a local dealer around me so I would have to drive around 200 miles to listen to any audio equipment, I just didn't have that much time for various reasons.  I found a PS Audio BHK 250 amp about a month before I got the speakers that Upscale Audio had on sale for a really good price, so I called and just happened to get Joel on the phone.  My first impression was wow this guys seems like he knows what he is talking about.  When I did finally decide to get new speakers I called Joel again to ask about the Sopra's and he assured me that they sounded great.  I went ahead and bought the speakers and could not be happier.  Joel definitely led me in the right direction.  Upscale and Kevin's team are awesome, I just wish I had the time to go to Laverne, CA to meet them in person. 

thank you guys, I too love upscaleaudio!

1 - compatibility 

2 - how it sounds, to my ears. 

I read reviews. Then I buy unseen/unheard. Tough to audition nowadays, all my hifi stores/haunts have shuttered. I am mostly pleased with what I’ve bought, which currently includes tannoy legacy eaton, Martin Logan motion 15, wharfedale diamond 225, and JBL 4309. This Is all in my wheelhouse right now. All have their own sound characteristics and all sound wonderfull, at least to my ears. Don’t ask about the other crap I own, it would take me an hour to list it all 🙄, it’s an illness.