Floorstanding speaker experiences/recommendations in the $12-25k range

@njkrebs Wilsons have a natural tone and the Sabrinas check all the boxes, however, your amp is slightly underpowered for these speakers in that size room. Depends on how loud you like to listen. 
Magico speakers do not sound anything like Wilsons. And even the A3 are power hungry and more so than the Sabrinas. 

I own and would not hesitate to recommend the Sabrinas. 

As to your other choices, not sure. Best is to go hear these speakers especially the Devore and the Borresen. As a side note, the claim that the $11,000 X3 compete with $25,000 speakers is ambitious. May be they do sound better than some mysterious $25,000 speakers but I’ll believe it when I see/hear it. It’s way too hyped up now. 

Please note up-front: I am not getting any financial reward from the following, or anything else, for that matter. All I want to do is sharing my everyday musical enjoyment.

To me - after decades of searching - there is only one answer to your question and your budgetary frame: Linkwitz LX521.4Mg (Magnesium Mid-Low). This is an entire package, not only the speaker, but includes an active ASP and 5 (!) amps per channel (10 total). All this fitting precisely into your price bracket. The Linkwitz 521.4 is the result of decades-long tinkering by the late Siegfried Linkwitz (of Linkwitz-Riley crossover fame) to create a sound transducer based on our scientific insights into the realm of psycho-acoustics, or simpler: how do we perceive music so that our brain can relax and not constantly has to recreate a musical event from imperfect acoustic clues. It is the latter demand on our brains that leads to listening fatigue. I will abstain to delve into a scientific description of why and how. Only so much: these are open-baffle dipole speakers; each speaker contains two subwoofers, one mid-woofer, one mid-high driver and two tweeters. The subs and the tweeters come in pairs, because one beams to the front  and the other to the rear. That makes for 5 separate drivers (the tweeters are wired in reverse series), each of which has its own amplifier (each sub has its own, i.e. 2/channel). Moreover, the ASP (analog signal processor), takes the signal coming from the preamp (or DAC) and splits it up in such a way that each driver gets only that part of the frequency spectrum where its response curves are more-or-less flat. This leads to an overall flat and well-balanced frequency response of the speaker. You can read about this in great detail on the Linkwitz Store website or on Siegfried's own Linkwitzlab site. The speakers can be bought completely assembled, turn-key, so to speak, or as a construction set, that ships like a piece of furniture from IKEA. The price difference is a whopping $10K. I built my speakers myself. There are numerous reviews on the web about this extraordinary system, and many best-in-show opinions from visitors at AXPONA or the Munich show. Most recently, Tom Martin (of Absolute Sound fame) reviewed the system on his blog site, and called it a true "breakthrough".

I myself could not think of a more enjoyable speaker, as it does bring the music venue into my room with a realism and 3D staging that is nothing short of uncanny, and does so effortlessly without any distortions of frequency shortcomings: the bass goes deep, and remains dry and superbly focused, while as loud as the recording demands. Well, two subs, each driven with 250 A, leave nothing on the table. I listen to every musical genre (except Grunge), and I have never felt that there should be more. I get great performances from intimate jazz lounge recordings and solo singers or instruments as well as from large-stage synthesizer-heavy stuff such as Dead Can Dance or the recent Blade Runner tracks, which are just mind-blowing.

I could get on and on, but I think you get my drift: for your budget there is simply nothing else out there coming even close to what the LX521 system offers. 

A final note: the Linkwitz store is direct-sale, no middle men, no mark-ups, no ad costs in magazines (besides a very small one in the recent Stereophile pages); however, if you are interested, many happy users such as myself have agreed to join the international network of Linkwitz Lounges, where we open our homes to perfect strangers and have them listening to our set-up, before they spend beaucoup-bucks on something which turns out to be a compromise. My lounge is located in our living room, meaning: a realistic setting, such as your own. There are no wall treatments or any other fancy stuff obfuscating the fact that a demo system could be far from perfect in your own setting. So, if you are serious and not too far from Silicon Valley, please shoot me a message and we go from there!

I’d suggest before making recommendations to take into account that the OP’s amp, while excellent, is a relatively low-powered tube amplifier. As per John Atkinson’s measurements of the amp it’s not comfortable driving speakers that dip to low impedance levels. From his measurements…

”Octave specifies the maximum power into 4 ohms with KT150 tubes as 120Wpc (17.8dBW), and fig.5 reveals that, with both channels operating, the amplifier just reached this power at 3% distortion. At our usual definition of clipping (1% THD), the amplifier gave 43.3Wpc into 4 ohms (13.35dBW) and 79Wpc into 8 ohms (19dBW).”

So recommending speakers like Revel, Wilson, Magico, Vivid, Dynaudio Confidence, KEF, etc. that aren’t really tube friendly — and especially not low-powered tube friendly — are likely not a good match for this amp as they’ll push it well out of its optimal operating range and into high distortion and poorly-controlled bass. Just something to consider for future recommendations.

I auditioned the Dynaudio floor standers and Magico A3's during the same session. I don't remember the model but as I recall the woofers were a little bigger and, the cabinet was bigger than the A3's.  I went with the Magicos. The Dynaudio's were nice but I thought the A3's beat them. 

That was over three years ago. I've been extremely happy with the A3's. I've updated all of my gear to bring out their potential but it's been worth the effort.

I’ll throw in my two cents worth for your consideration. I’ve cycled through three pairs of speakers — B&W bookshelves, Usher MD2, and currently, what I think will be the last speakers I ever purchase — the Scansonic MB6-B.

Scansonic is the value line of the well regarded (but very expensive) Raidho speakers of Denmark. They are tall, sleek, and sound exquisite — detailed, amazing soundstage and depth, fast, and with incredible range. I have two REL subs in my system and haven’t bothered to turn them on — the Scans do perfectly well hitting the lower frequencies on their own. They retail for $15k.

The MB6-Bs were designed by Michael Borresen who later went on to found his own audiophile company bearing his name and producing outstanding loudspeakers including the Borresen X-3. I considered them when I purchased the Scans — to my ear it was a toss up. Both were amazing loudspeakers at an even more amazing price — between $12-$15k. They were  the best values I could find and certainly kept pace with the Sabrinas that I had longed dreamed of owning.

For context, my equipment is based on Parasound electronics including JC1 monoblocks, JC2 BP pre-amp, JC3 phono amp, and a CD-1 CD player. My primary source is vinyl played on a VPI Scout turntable with a Dynavector 20X2-L cartridge. And the two REL subs mentioned above now get used only with my home theater system.

The Scansonic aren’t well known in the states and you’ll have to dig to find reviews. But with one exception where the reviewer didn’t like the technical “measurements” of the speakers, all of the others I found came to the same conclusion I did — these are amazing loudspeakers that will give you hours of musical enjoyment. 

I first discovered and listened to the MB6-Bs at AXPONA 2023. That was it, I was hooked and purchased them by the end of the month!

Best of luck with your search — enjoy the ride!