Efficient speaker: Zu, Tekton, Volti, Klipsch, Fleetwood?

It all really comes down to personal taste.  I've only heard Zu and Tekton at shows so I don't have much to offer on those.  I've owned Forte IIIs and have upgraded those to Volti Razz and from the Razz to Volti Rivals.  I wrote a quick review for Greg for the Razz that's on his site and can be found here (it's the one that mentions the Forte IIIs): https://voltiaudio.com/razz-press/

He also left the link up for the Rivals that I have now which are here: https://voltiaudio.com/RivalSErosewood.shtml

I liked all three speakers but I can't foresee ever getting rid of the Rivals.  I think you will find any of these pretty different from the Super 9s, which I think are definitely a little hotter on the top end (a local dealer sells them and I've auditioned them twice).  The Rivals are being driven by an LTA Z40i w/Mullards (updated to the latest version a couple of weeks ago) and the main source is an Innous Zenith music server going into a Border Patrol SE-I DAC.  I'll add a turntable this year.

I have another system that I've been deciding whether to do something similar or something completely different and after toying with the idea of speakers from Marten, QLN and Joseph Audio (which are all great) I decided I kind of love horns and bought a pair of Fleetwood Deville's yesterday.  The Deville's throw out just an unbelievably layered soundstage and the way voices and instruments just kind of fall out of the speakers in an effortless way is pretty intoxicating.  For me, it's all about engagement.  I either find the music coming from speaker X engaging or not, and the one I want to keep listening to is always the right choice.  It sounds obvious, but trust me more folks end up buying based on some perceived audiophile trait than don't.  The other speaker that I really love (but it's a bit too nearfield for my room) is the Harbeth 30.2 (just to draw a reference point for you).  I hope some of this helps.  Good luck.

@facten The room is basically 13'x23'.  They will be set up on the short wall about 6' into the room.

@ladok If you are seriously looking at the Zu stuff, I would use a little caution.  As mentioned elsewhere, people either love them or hate them.  I've only heard them at shows and as much as I want to like them, I never do.  I am going to hear a pair with some really nice amplification in the next couple of weeks and am anxious to hear a pair well set up and not at a show.  Hope I hear what everyone loves about them.  The moral of the story is to make sure you hear these before taking the plunge on them.

Greg at Volti used to do a little demo that was based on his work fixing older KHorns.  He would just speak through one of the KHorn assemblies and then speak through one of his versions.  It was a pretty startling comparison, the original sounded like his voice was coming out of a tunnel while his improved version sounds like his voice.  I owned a pair of Forte IIIs and actually traded them to Greg as part of my original purchase of the Razz.  He likes the Forte IIIs, as did I--but the Razz are clearly better and the Rivals are better yet.

That said, think the corner horns are really cool if you have the room set up and the space for them, but I imagine lots of folks don't.  I've got some big spaces in my home, but not two corners that would work in any room big enough to accommodate them--at least not if I want to stay married!