If you have an EQ pedal, you can get very close to the sound of an acoustic simulator pedal by using a deep-V shape. That's what I do when I need "that sound." If that's not good enough, I plug in a real acoustic.
It is kind of a specialized eq, but it does add a little something else - some kind of depth to the sound. But, I've bought and sold the AC3 twice. I really wanted to like it, but could never bring myself to use it live. I suppose for one, I've got limited space on my board, and it couldn't compete.
Perhaps my main problem is that I am already a bit of an acoustic tone snob - spent as much, if not more, on my acoustic amps, pedals, pickups and guitars as I've spent on my electric setup. So, pretty much, if I want an acoustic touch in a set, I will bring my acoustic.
The overall sound is pretty thin.
The reverb on the AC3 is actually pretty decent, and adds quite a nice touch, and helps give some good dimension to the sound.
I know they say that you should run the "line out" from it to a full range PA rather than a guitar amp. Makes sense, but then it has this terrible hiss that it emits (I think they were going for "air" in the sound). To me, it's too noisy. I've tried it through other pedals with tube emulation to tame the high end, and that helped to both thicken the sound and reduce the hiss. But, I've found it rather disappointing overall.
Just my thoughts. Hope it helps.
Don't listen to these guys. The AC-3 sounds great. I don't see the point in calling it thin when there's really nothing to compare it to. Yes an EQ pedal would help after the AC-3 but an EQ on it's own won't get you there at all. I gig with mine with a Strat just fine.