I've used imovie in the past for very basic editing and exporting of movies. As far as music creation goes, I've never done anything serious in garage band, but it seems recently it's gotten to be much more powerful.
I used to make music on my laptop MAC OS X Lion, then had the idea to install Cubase on my desktop PC, since then I've sold my laptop. But I must say iDevices exclusives free sruffs was interesting, like iRecorder, thats how I've recoreded the voices of my first EP, but it's useless to me now that I'll probably buy an external sound card with microphones.
I like using GarageBand to make my music along side a app called alchemy, and I movie to make my videos, does anyone else find these good cheap ways of doing things?
iMovie is great for doing casual stuff. I can get a nice little project finished in less time then it would take me to set up the basic project in Premiere. All of these dumbed down tools have their limitations and they can be quite obvious. On the other hand, they are great for just getting some stuff done.
I'm recording a new 12 track album, and 1 instrumental was entirely created in Garage Band before I paid for Logic.
I like Garage Band. It's actually quite powerful, although the interface leaves a lot to ne desired with no full mixing desk, etc. I've never tried iMovie
In my hometown, the folks at GuitarCenter don't know anything about PC's because they only use GarageBand. Ask em any mac question and they know it, but any PC thing and they can't answer even if it's about controllers. That's all I know about it. I never really tried it much.