5 stars (I had to respond) - I've got to say that this unit works perfectly with my wife's powerbook. Unlike other posters, I had NO problems with it at all on my G5 at work, my G4 at home and her powerbook. The sound is fantastic and it works really well with the Apple audio control program which recognizes it right away. My setup for mic level input includes a professional mic which is amplified by a separate mic amp. The output of that line level amp feeds right into this unit. Additionally, the sound output to my headphones is a step above what is built into my G5. 4 stars (Great unit with the Mac and podcasting) - I have had ZERO problems with this unit. It's plug and play on my Apple G4 tower running OS X (Panther) as well as my PowerBook G4. I use the Fast Track with Audio Hijack Pro, Detour , Soundflower, Audacity and it works like a charm. The only thing lacking is phantom power for a microphone, which I solved with an ART tube preamp which you can get on Amazon for about $50 U.S. 1 stars (Hmmm not quite sure!!!????) - I ve given this 1 star because i cant get it to work properly with my ibook!. Not sure about windows users though. It doesnt work with any of my programs , guitar rig , gt express (which comes bundled with the product!!!!!) and garage band. The company advertises this product as perfect for garageband. I've also read in other forums that the low latency is rubbish. Buy at your own peril!!!!!!!! ... M-Audio :: guitar; vocal; vocals; record; pc; mac; :: Sequencing :: Creation :: audio :: Music :: Computer software (programs) :: :: M-Audio Fast Track US44010 USB Audio Interface