Boutique or Big Brand?

1. That's a great range for a set of speakers.

2. I won't mentions brands I have purchased, owned... because there are so many variables. 

3. To your question, I'd add, check on customer service. I've had some products that needed service - good luck trying to get support AND some that had excellent service. 

4. Ask others who have the products you settle on and read reviews. 

If buying new I would go with a boutique brand. People say all kinds of BS about the Tekton’s cheap drivers and all that. They actually are pretty good drivers and implemented well. I doubt you could diy most Tektons for what they cost. My old DIs did some things better than way more expensive speakers. No I don’t think they were better than most 30k speakers as the hype says. They were however I’m pretty sure better than anything else at 3k or even in the ballpark. 
 

On the other hand if I was spending 5k it would not be new speakers. 5k gets you a hell of a speaker if willing to buy used. Think 10-12 years old speakers that were 10-15k at the time you can get for %75 off. Not much risk there. My Pioneer S-1ex are better than the Tektons and I paid the same for at the time. 
 

Ramping that budget up to 15-20k I don’t know. Probably some Focal Sopra. 

One thing I'd add that hasn't been mentioned- when you narrow it down, message a few members that have owned the speakers you are looking at. I always reply and those that I've contact reply too. It can be a good way to get a little deeper and maybe get some better opinions before purchasing.

Good luck you will find something nice in that range, especially if you decide to buy used.

You didnot mention one very big factor your rooms dimentions.

spatial audio technologies makes some excellent open baffle speakers that are very efficient  and on several models powered Bass well worth the effort even if it meant saving $1-2 k more the Beyma Mid-Tweeter alone is world class, plus a 12 inch midBass driver. And powered bass driver .I don’t currently own his newest but have heard them , at least  give them a look.

I went on a year-long speaker search around the USA.  I listened to at least 50 different brands.  My suggestion is to attend an audio show if you can.  At least there is a wide variety of speakers that you can listen to.  I traveled the NY / NJ markets and the LA / San Diego markets.  So many dealers and so many options to hear speakers in those markets.  

I had previously owned Wilson and Sonus Faber speakers.  After it was all said and done I went with a small boutique company out of New Mexico called Viking Acoustics.  Why?  Because they could tailor the speaker to my exact listening sound characteristics.  The well-known brands would not do that.  It turns out that my current speakers are way better than my Wilson or SF speakers for less money.  BTW, they personally delivered the speakers to my house and set them up for me.  That was an 8-hour drive.  

From a boutique perspective, take a look at Charney Audio or Salk, or Joseph Audio.  I have heard a ton of good comments on Fyne Speakers.  

I have Tekton speakers in my theater room.  You can do better my friend.

Don't be in a rush.  Enjoy the process and the ride.