Soundtrack is a GREAT little application for creating "original" music for your video / dvd / web projects out of the roughly 4000 (if memory serves) supplied clips.
I just took delivery of my copy of Soundtrack two days ago; it's been a long time since I've had so much fun with a program. Other programs are powerful (photoshop) but tedious to use to get great results. Soundtrack is quick, easy and effective at what it does.
You don't need to know anything about music to get rolling with it. However, to make a nice composition with the loops, some basic knowledge would help.
For those who spend hours looking for just the right song - soundtrack is your new best friend. Best of all, it's royalty free, so you don't have to worry about getting sued if your little project makes it big!
The one downside I have found (in two days, so I could be wrong) is that while you can create some great beats while choosing from some quite diverse instruments - there are few "fills" or transitions to get you from one phrase to the next or to open your piece.
This is NOT a Finale killer. Some of the wording on the Apple site makes it sound as if you could do similar things to finale. In particular, the Apple site says "compose music." Well, you can't write music from scratch - but that's the joy of soundtrack.
So far the diversity of sounds and loops has been very nice and I look forward to adding my own to the program.
I highly recommend this software to those with Final Cut Express (it's included with Pro) DVDSP, iMovie, iDVD or any other program without soundtrack. Soundtrack is flat out great.