I'm just finishing the first album project I've had since I've received my mics. My assessment is this:
ACM-3
These are dark. The top sounds rolled off and the bottom is woolly. I'm guessing there is a bump in the neighborhood of 400 Hz. They sound good in front of a guitar amp, but honestly, I haven't actually used any of the tracks I recorded with these. I am going to pass these off to Marik to work his magic with at some point.
ACM-70
These I like. I would guess that giving this sized ribbon the extra 10 or so mm to play with has paid off. They definitely aren't transparent but they are much flatter than the ACM-3's. The hf rolloff is much more natural sounding and the lf bump seems closer to 200 Hz making it much easier to deal with. I've used them on guitar amps and horns and I'm very pleased with the results. Let's be clear, these ain't a pair of Coles, but they have a sound all their own and you can reap the "ribbon mic benefits" with these quite nicely.
ACM-1200
I'll break my assessment of these into two categories: Close and far... Very different results....
Close: In our vocal mic shootout, the 1200 was up against a 414, an 87, a Gefell MT711s, etc and I can honestly say I couldn't hear the difference between it and the 414. Neither of those mics was the right choice for this guy, but still, I was impressed in how well it held it's own. That said, it's bright and I already have a 414 and don't really need any more.
Far: As drum room mics: meh. They worked fine, but they definitely lack depth and detail. Because of the hf bump, the minute you start compressing them, the cymbals get pretty trashy sounding. I found it challenging to get the snare room sound I wanted without destroying the rest of the kit. That said, I eventually met that challenge and like the drum sound I got in the end.
I have a pair of Dale M7s on the way for these so I'm really looking forward to modding the crap out of them. I'm going to change the transformers, swap out some components, reign in the voltages and remove the CF in one of them so I can do a direct comparison. I don't think the capsules are as bad as people say, but the sound of these mics isn't as "special" as a good tube mic should sound. Of course I payed like $100 each for these so I ain't complaining. As a matter of fact, all things considered, I think I made out like a bandit.
Anywho, I'm posting mixes here as I finish them:
http://www.dibsreaction.com/2009/04/10/apollo-run/
If anyone wants to hear specific splits in the interest of mic research, I'd be happy to post them.