AA3 is my second-most-used tool, second only to SONAR. The multi-track capability is of no interest to me, as Adobe abandoned that development arc before it was fully fleshed-out. It's nowhere near the same league as SONAR in that respect.
However, as an audio editor it nicely complements all the stuff that SONAR doesn't have and probably never will have: click/pop/hiss removal, spectral editing, analysis, MP3 encoding, file conversion, test-tone generation and special effects. It's a Swiss Army knife for audio.
Don't bother with the loops, though. It's a huge download and IMO not at all useful. But then, I don't do loops.