My favorite of those I have heard were the Acoustat 3's. I think they made some 6's which were like 3+3's and likely would have liked them. One thing I like about my Soundlabs which share a lot of design similarity with the Acoustat is they don't have a plastic quality to them, and panels have a gentle curve rather than angled flat panels side by side.
Model 3 was flat and wide, whereas Model 2 (and the 2+) was tall and slim. It really depended on your listening space--how much room to move you had. And of course your pocketbook. Tall and slim was certainly easier to place within most domestic settings. Since the speakers did best (IMO) in a more open space, for a good sounding 3 and/or 6 you wanted a pretty large listening area. I suppose that it true of any oversized panel.
I also spent time with Soundlabs (not mine, and not in my home). To me, they were much better sonically, but much more expensive.
Acoustats generally were more affordable than the usual electrostatic thing. The company attempted to go 'downmarket' with a line of hybrids, incorporating an integrated woofer below the panel section, but the integration was not particularly successful to my ears. My brother in law had a set of those, and I never could get them to sound as coherent as the 'full range' models. I think at their price point a dynamic loudspeaker would have been better.
Acoustat merged into the Hafler/Rockford group, and was left to flounder. Jim Strickland (the man behind Acoustat) incorporated some of his electronic designs into Hafler amps, but by then Hafler was concentrating on the 'pro' market, having left the DIY consumer scene. For their part, Rockford understood that aftermarket car audio was the money maker, and acted accordingly. I read somewhere that the name was sold to an Italian company, and then to a Chinese company. But it's been decades.
Hafler was acquired by Radial, but I don't know about the brand's market penetration. Radial also attempted to bring a 'modern' version of the Dynaco ST-70 to market, with results that were pretty much expected.
With Acoustat's decline, my dealer dropped the franchise, substituting the Magneplanar product. I never thought those were as sonically sound as what came before, but Magneplanar is still in business, still offering viable product to customers who are looking for that sort of thing. So they win.
Another aside: I owned both the larger Acoustat amplifier and matching preamp. The preamp developed some switch/attenuator noise, but I had a lot of gear do that. I was living in Central Florida at the time, and now wonder if the overwhelming humidity had a negative effect on electronic gear, in general? I wonder whether living in Arizona, or New Mexico, or one of the other venues that rust forgot, would be better on electronics?