I was there in the beginning. A breakthrough product that could take recorded audio and synchronize it to any tempo and even change it pitch to fit any key (all within reason).
But then people in offices took over the development of Acid and they didn't have a cussing clue what made the program valuable, special even.
So, they decided to steer Acid away from being a monster loop based app to a full fledged DAW.
It failed, of course. Acid will never compete with Logic, Pro Tools, Cubase, or other DAW apps.
But what's really sad, is now, Acid doesn't really even compete with other loop based editors. Every time a new version comes out, I run through a series of tests to see if Acid has improved even slightly at rendering audio in sync. It hasn't.
As far as I can see, Acid's looping technology hasn't been improved in more than 10 years. It still can't accurately detect hit points in non-Acidized audio. It still can't pitch shift audio very well. You still can't tell it what scale it should be. It exactly the same as it was in, at least, ver. 4 and probably earlier.
Now, Magix, a consumer software company that now owns formerly pro software, has bought it. What is their big new innovation? They changed the color of the UI. Now it's black and dark gray, like every other audio app these days.
Clearly, the business model here is to try and trick people into thinking there's something new here when, under the hood, it's Acid 4 with a few new effects and low budget virtual instruments.
Don't get me wrong. I still bought Acid 8. But not for me. I bought it for my children as a fun toy to play with.
But there was a time when Acid had pro audio applications. And it still could. No other app, including Ableton, makes adding loop based percussion as easy. Cubase's loop browser is horrible. Logic's non-existent. But Acid still is the best at auditioning loops on the fly, a critical function for building loop based percussion.
It used to be really cool to render a rough mix of a track, port it into Acid, and then using Acid's superior loop browser and synchronization capabilities, build some awesome percussion tracks on top, then export out and back into the project in the DAW (or use rewire for I/O).
You can still do all this. And I can tell you the best program to do it in: Acid 4.