Horn based loudspeakers why the controversy?

Horns were virtually ignored by the "high-end" journals like TAS and the Stereophile back in the day. The transition to solid state probably didn’t help either, given that a lot of early sound state gear could be rough on the ears. Size mattered too- I had an older friend while I was finishing college who ran a pair of old K-horns with then already vintage Marantz tube gear and it sounded pretty good. (At the time I was using the original Quad ESL and Audio Research tube amp and preamp).
The notion of vintage horns like WE, RCA, JBL, etc. seemed pretty removed from the collective wisdom being preached in the era when I started fooling around with "serious" gear--the very early ’70s. I think it wasn’t promoted, manufactured or sold much in the States for consumer audio, and certainly wasn’t given the imprimatur of the authorities of the day (back when reading Harry Pearson and J.G. Holt was meaningful-i think people are far more skeptical of reviews and reviewers today, which is a different subject).
I know there were hardcore horn enthusiasts in the Far East. And perhaps a few on the fringes here in the States.
What products revived the horn? Avantgarde was certainly one; there are probably some others, of recent manufacture within the last ten years, along with greater awareness of vintage equipment, like idler turntables and SET amps. (My Avantgardes didn’t really sing until I got a pair of Lamm ML2s).
A hybrid horn system is still a challenge--matching woofer characteristics to the mid and high frequency horns. A full horn system including bass horns is not only large but unless you are DIY, costly. (Even DIY is costly if you are using vintage or more modern high end compression drivers).
I know some people that visited me over the years were surprised that there was no "shouty" ear bleeding aspect to the system--part of it was set up, and a lot had to do with associated components. I’m not sure how effectively horns have been demonstrated at hi-fi shows after their modern resurgence (I don’t go to audio shows much any more).
I also don’t listen at crazy high dbs. In fact, I can get a lot of information at low volume levels, but the bass (I supplement with 15 inch servo woofers, not ideal, but cost-effective) doesn’t really come alive until the system is played at "normal" listening levels. I think the dynamic capabilities aren’t just about "peak loudness" but the so-called ’jump factor’- the ability of the system to make those dynamic swings effortlessly. As a decades long Quad listener (still have ’em, just got ’em restored), I’ve always been about the midrange first- open, non-grainy, not "reproduced" sounding. Horns give me that. The Quads are easier to set up but have even greater limitations. I love both.
I’ve heard very convincing conventional coned speakers- such as the Rockports, driven by very substantial amplification and a good analog front end. Such systems do some things better (at least in the bass region, unless you have horn woofers).
It’s all trade-offs somewhere. Pick your preference. I’ve been extremely happy with my horn system for the past 11 years, and know that I could do better if I threw more money at it.
For the last few years, my priority has been obtaining records. The system is sufficiently "good" that I’d rather have more, different, and interesting music to listen to than constantly upgrade gear.

@james1969 - no, i have not used the ML2s on the Quads (yet). I had my old Quad II amps restored, and installed NOS GEC KT 66s, NIB GEC EF86 and a NOS Mullard rectifier. They are fab sounding- better than when I first started using them in 1973.
I did use super tweets (Deccas; Sequerra Ribbons) and a woofer back in the day; the tweeters were fine, getting the bass seamless was very difficult, perhaps owing to what was available commercially in the late ’70s and early ’80s. I then switched to the Crosby Quad for a long while and shelved the original ESLs until recently restored.
The woofer matching with the horns is very similar to the experience I had with the Quads. Right now, I’m using the Quads without any additional speaker(s).
With the Avantgarde, I found that if you cranked up the woofer gain to make it punch, it sounded obviously discontinuous with the mid-horn; back the woofer off to blend with the mid-horn made the bass reticent; thus, I supplement with those add-on 15" servo subwoofers. I matched the sound of subs to blend into the Avantgarde woofers as seamlessly as possible through adjustments to crossovers, gain and on the subs, phase. I also added a small DSP unit to the subs. You really don’t notice them, except they give a deeper, bigger stage and when there is real deep bass on a record, it is now presented with more authority.
I’d love to do a semi-vintage horn system; just a question of dollars at this point. I’m a retired pensioner living on my investments. :)
Are you using your Lamms with the Klipsch you linked to?

@james1969 - I sent you a PM via Audiogon so we don't have to burden this thread with our Quad discussion. 
regards,
bill