I personally think the "does it sound like a real 303?" is a totally irrelevant discussion - if it sounds good and it's nice to use, then go ahead and do that acid. No one's gonna care how it was made. I've used some older version of ABL and thought it was pretty good. D16's Phoscyon is also nice. I've also used the real thing, and a bunch of hardware clones - they all sound a bit different, but it's well possible to make acid with each and every one of them.