That depends on your goals and ambitions. It will serve all your basic recording, mixing and production needs, and many, many bands and solo musicians are taking their first steps with home recording using Garage Band, or similar software packages on other platforms.
I spent many hours playing with a Fostex 4-track tape recorder when I was a kid. I wish I'd had the kind of power and flexibility Garage Band could have given me back then. I think the strongest appeal of Garage Band is that it is not just a watered down version of a feature-packed audio production software, but designed from the ground up to simple to use. I think most beginners will not feel limited by the options and features available in Garage Band. Like most other DAW-software, everything evolves around tracks in GarageBand. Each track has a horizontal lanes. Audio samples or MIDI notes are displayed as colored strips. The right side of each horizontal lane contains basic mixing controls--a fader, pan-pot, effects, as well as a VU-meter with digital clipping indication. Those controls can be automated.
Both Logic and GarageBand use the Audio Unit plugin interface. I believe that means any Audio Unit plugin can be used with GarageBand, although I haven't actually tried that.
You can record up to eight tracks simultaneously with GarageBand to either four stereo tracks, eight mono tracks, or any combination in between.
Limitations: The mixing model implemented in GarageBand doesn't try to mimic a real-world mixer with sends and buses.
- No effect send & return channels and no buses for grouping effects on multiple channels.
- No effects on the master output.
Price: GarageBand only cost a fraction of the big DAW software packages.
You can find lots of other differences when you compare GarageBand with other DAW software, but the question again is, what do you need? What are your must-have features?
Given the low price, I would say give it a spin, see if it works for you.