Even over my 933Mhz G4 w/ 1.5GB RAM it was quite noticeable.
I use it for everything I normally do with my MacBook. I ripped a 9GB DVD down to 4.7GB in a matter of 20 minutes. Not bad for how much time my G4 took. iirc, the MacBook took something like 7 minutes. So it would do great for A/V
I like the fact I can still use PCI Cards, even if I am stuck at AGP for the video. *sigh* some day I will max this out, but that time is not now...