It’s lovely choice to make. I’m not sure the Everest can be driven by the usual SET amps- they are efficient but not crazy efficient. That would be the chief benefit of the Avantgarde, though bass integration has always been the trick: I have older Duos and have gotten them as good as i think they can be in that regard, save for having Jim Smith (the original importer and known set-up guru) spend time voicing the system. The Duo Mezzo with larger, horn loaded woofers may have considerably improved that integration issue, but, for me, on the older Duo, it was very tricky to get the bass to cohere with the mids- set for "good bass" in the room, there was discontinuity and set to match the horns, the speaker sounded bass-shy. (As I said, this may be less an issue given the woofers on the Mezzo).
I use relatively low powered SETs (Lamm ML2- not flea power) and the horn-SET combo can deliver magic on good recordings. The JBL is marvelous- not having heard the latest and greatest, but have heard the K2 driven by a ViVa amp (which as I recall was a lower powered SET) and it was wonderful-very in the room, no sense of a speaker, or system reproducing sound.
I think the JBL new is heavily discounted at least in the States, or seems to be judging by listings here. Perhaps it depends on where you are located; not so sure about new Avantgardes. Audiogon member Eberroth has a set of Mezzo Duos for sale here (I think he’s in Poland- don’t know him personally but know his name from audio stuff).
You should hear these things yourself- everyone is going to have their own preference; I suspect the JBL may be a little more coherent top to bottom but probably not quite as invisible in the midrange as the Avantgarde, given the two things: if the Duo Mezzo is anything like the older Duo I have, there is no crossover on the mid horn. None. So, hooking up an SET amp like the Lamm (which has a particular synergy with the Avantgardes), will give you a sound that has almost no barrier between the recording, the system and you on well recorded records.
You need to talk to the Great Karmeli (A-gon member DDK) who has some major antiquarian horns, JBLs and uses Lamms though I think he uses multiple amps for his JBLs, so your cost factor on amplification is doubled, if I am correct.
I was a Quad listener for decades, first the original Quad (which I supplemented, never satisfactorily, with ribbons and woofers) and later, the Crosby Quad. I switched to horns and SET amplification in 2006-7, and haven’t looked back. Very "in the room," alive, dynamic and don’t miss a thing in the midrange, which is always where I first get engaged or turned-off; if the midrange is boxy, grainy or sounds reproduced, that’s a big "tell" for me that the gear is getting in the way.
Take my observations for what they are worth- I think you have to hear them both with appropriate amplification and decide for yourself what suits over a range of recordings, not just a few cherry picked demo records.
One last observation- at least insofar as the Avantgarde experience is concerned- the speaker is very sensitive to associated gear and getting everything "just so" takes some time. (Perhaps that’s true of all good gear, but my system got progressively better as I upgraded gear upstream in the chain and spent time dialing everything in over a long term period).
I use relatively low powered SETs (Lamm ML2- not flea power) and the horn-SET combo can deliver magic on good recordings. The JBL is marvelous- not having heard the latest and greatest, but have heard the K2 driven by a ViVa amp (which as I recall was a lower powered SET) and it was wonderful-very in the room, no sense of a speaker, or system reproducing sound.
I think the JBL new is heavily discounted at least in the States, or seems to be judging by listings here. Perhaps it depends on where you are located; not so sure about new Avantgardes. Audiogon member Eberroth has a set of Mezzo Duos for sale here (I think he’s in Poland- don’t know him personally but know his name from audio stuff).
You should hear these things yourself- everyone is going to have their own preference; I suspect the JBL may be a little more coherent top to bottom but probably not quite as invisible in the midrange as the Avantgarde, given the two things: if the Duo Mezzo is anything like the older Duo I have, there is no crossover on the mid horn. None. So, hooking up an SET amp like the Lamm (which has a particular synergy with the Avantgardes), will give you a sound that has almost no barrier between the recording, the system and you on well recorded records.
You need to talk to the Great Karmeli (A-gon member DDK) who has some major antiquarian horns, JBLs and uses Lamms though I think he uses multiple amps for his JBLs, so your cost factor on amplification is doubled, if I am correct.
I was a Quad listener for decades, first the original Quad (which I supplemented, never satisfactorily, with ribbons and woofers) and later, the Crosby Quad. I switched to horns and SET amplification in 2006-7, and haven’t looked back. Very "in the room," alive, dynamic and don’t miss a thing in the midrange, which is always where I first get engaged or turned-off; if the midrange is boxy, grainy or sounds reproduced, that’s a big "tell" for me that the gear is getting in the way.
Take my observations for what they are worth- I think you have to hear them both with appropriate amplification and decide for yourself what suits over a range of recordings, not just a few cherry picked demo records.
One last observation- at least insofar as the Avantgarde experience is concerned- the speaker is very sensitive to associated gear and getting everything "just so" takes some time. (Perhaps that’s true of all good gear, but my system got progressively better as I upgraded gear upstream in the chain and spent time dialing everything in over a long term period).