I have both cameras. They are virtually identical, so much so that it is a puzzle while D-Link made the model switch. And annoying, too, because the 2332 firmware still needs work, and now it won't get it. Meanwhile, the 2330 firmware is a new build (back to v1.0) and it has different issues.
Anyway -- yes, the 2330 can trigger alerts based on audio detection, which the 2332 could not (although I suspect that it was capable of it, but this feature was never enabled in the firmware). The 2330 has a few other very minor firmware additions, for example the ability to reboot the camera on a schedule, but aside from audio alerts, the major features are exactly the same. Also yes, the vertical resolution has been decreased to 720 pixels from 800.
The performance of the two models is similar. Motion detection, whether via PIR or software, is about as effective (or ineffective, depending on your view) between the two. Overall I have found the 2332 to be more stable than the 2330, although I've not had issues with the 2330 lately.