Yeah, I read a nice thread about AM a while back. This one, right? http://www.elektronauts.com/t/amplitude-modulation/431
A nice read for understanding how the AM feature is implemented.
My problem was not understanding the feature, though. I just wasn’t able to create any nice-sounding patches with it. Hardwired 100% pulse modulation just seemed crazy at first. But dumbledogs tips helped me get past that.
…and yeah, I love the feedback oscillator. Having tons of fun with that. 
I must admit I was a bit underwhelmed by the a4 sound engine when I first bought it, but I slowly realize there is much more to discover and explore than I first thought. it is my lack of skills that is limiting me, not the instrument.