I don't own any Audient product but a friend of mine does and he let me borrow his for a week. He has the ID14. From my observation the mic preamps and DI are top notch, especially in that price range and the ad/da converters(Burr Brown) sound really good. As far as I know, the ID4 has the same Mic preamps and DI as the ID14 but not the same ad/da converters but from what I read here from other users they sound really good as well. My only complaint was that the latency on Win 7 64 was a bit too high for my needs (soft synths and guitar amp soft emulators). On Mac it uses MAC OSX drivers that are included by Apple which fares better than the PC drivers. I did hear that Audient upgraded their PC drivers for better low latency but I haven't heard any user feedback here regarding that yet.