Loads has been written the AER Pnoe, maybe before you became active on the forum. The AER driver is probably the best driver, maybe Feastrex is great (which I havent't heard so I cannot say). I am not mentioning my favorite horns here because in some ways this is a pointless thread asking what are your favorite speakers, I have written about a lot of them. I was just responding to comments here on Trios and Tune Audio when they came up, but AER Pnoe is far superior
There is a very detailed thread on the AER on DIY audio by a Russian named Murat. He is one of the most methodical and sensible documenter I have come across on any forum, who went through a range of drivers from TAD, ALE, Goto, etc which he has detailed beautifully before landing on the AER highs with Goto bass. Another billionaire in Russia owned AER crossed over to Maxxonic woofers. I posted a lot of Murat's videos on the forum. He was well ahead of his time to document his research using accompanying videos.
Bill and I wrote about AER because we heard the General's system, which Ron later heard and wrote about it as the best system he had heard as well. I have heard the AER Pnoe in Genera'l's, in another place with some SETs, then obviously at Munich. At the General's It sounded better than almost all systems I have heard anywhere, while it sounded among the worst at Munich. Also, it was highly sensitive to any change anywhere in the chain. I later realized talking to those who have built speakers that this is due to being crossoverless - such speakers are like microscopes and very sensitive to changes. There are very few crossoverless speakers (I have heard the AER Pnoe, Loth MInistrel (stamm drivers), Yamamura). There were the Carfrae horns based on Lowther which might take the AER, and there is someone in NJ who makes some based on AER.
To me it indeed is the best commercial horn available and can be DIYed to the same, but it is a bit weird in terms of the fact that it is going to sound sh*t till you get it awesome, and even then it will be restricted to mainly classical and jazz. It is also the most sensitive speaker I have heard to showing differences between originals and reissues, and reissues sounded extremely poor. Just this week I was listening to a Fostex 3-way and the guy who had built it said while building he ran the Fostex midrange driver (which covers from just under 100hz all the way to 7khz) on its own for a while without a crossover, and it showed a massive variance to recordings until he put the crossovers in. Even then there was a difference but it was much less and it made reissues enjoyable. Fyi, best I heard reissues relative to originals were in DSPed systems.
But yes, if I had a lot of money today I could easily see myself loading up on original LPs first, then buying a Pnoe AER and running it with sub-5 watt amps on type 46, 45, 50, 2a3, and many other such valves, and the red sparrow on a linear tracker like Vyger.
That said, it is much easier to buy an AG trio, just plug it in to digital or low quality LPs, and get it sounding good right out of the box for all genres of music. Plus, it is much more widely distributed and serviced.