Efficient speakers -- What was your journey from A to B to ?

This thread is for people who have tried a successive number of efficient speakers and are willing to relate what they learned on the way.

Here's where I am: Recent experiences with speakers and amps has lead me toward lower watt (not ultra low) amps and more sensitive speakers.

I currently am looking for a second pair of speakers to alternate with my Ascends which would play more nicely with my Quicksilver Mono 60s and my Pass XA 25. (If I found the right speakers, I could be willing to look into SET amps, etc. but that is not my quest, now.)

I am open to design -- horns, open baffle, single driver, etc. My budget is flexible but I won't spend tens of thousands. So, some options are likely not possible.

Here are the speakers I am keeping an eye out for, used, but please add to my list! 

Audio Note
Coherent Audio 
Coincident — planar magnetic tweeters
Daedalus
Fyne
Klipsch
legacy
Living Voice 
Omega
Pure Audio Project
spatial
Tannoy
Volti

Again, I'm especially interested in hearing from folks who have tried more than one of these speakers and can explain what lead them from one brand or model to the next -- and why.

Thanks!