I don’t have much to add but have been using horn speakers (JBL 4367) for about a year now.

One thing I will say is there is almost always a trade off with bass extension. You are either going to have huge speakers or no bass depth if you want high efficiency. I personally think the solution is to add subs unless you have a very large budget.

For me the advantages (dynamics) out weigh the negatives. I will be using horns longterm at this point. It has been a revelation for me, everything just sounds less produced.

@hilde45 Not to trash on Devore, but I agree. I’ve had a few of John’s speakers on my floor, and they are too overpriced for their performance IMHO. The outside cabinets are attractive, but the innards leave much to be desired. They are not bad sounding, but there are many better alternatives in the market, many which are already mentioned on this thread. 

@james633 I have 3 subs and miniDSP to dial them in, so your suggestion is very apropos. Thanks.

@blisshifi They are very "cool" speakers and I've liked them when I heard them, but for my tastes and wallet, I've moved away from an early fixation on them. There's a lot out there and everyone has to decide what has value, but for their price -- $15,900 MSRP -- one would have to be comfortable leaving a lot of other options in the dust. That does not add up for me.

As a DIY’er and if I did not already build my own, and I was on a path for my next fleawatt amp efficiency speakers out there in DIY form, I’d be tempted to try one of Troel’s higher efficiency DIY offerings. Kinda cool, seems like a value to review. Lots of happy owners out there. Have not heard them though... nice parts. http://www.troelsgravesen.dk/HESintro.htm

JBL M2 Deep Dive