pretty much, some pregrams are limiting and there is now way around it, but in genereal if any particular person (who, for now is being the engineer) feels particularly comfortable using a particular program, have at it. i would, recommend though, since you are planning on mixing with this program, compare the available effects on the programs you are considering, and the GUI, and the ease of using all the effects (EQ and dynamics included), or find someone like me in your area (im in oregon) that has started a recording studio, and has specific prices for lower-quality 'quicky' demos for your situation.
to answer the orginal question quickly, i don't konw of Garage band, i konw CEP 2.0 quite thouroughly, and ProTools a little (although that is soon to change to a lot more). Cool Edit would be an excellent choice for your situation
-Keith