What's the difference between Apple's Logic Express & Logic Studio?

I wonder which I'd need. I just got the Blue USB external Microphone & notice a quality improvement. For creating MP3 or other standard audio files (not singing, rather lecturing).

Do I even need Logic Studio or Express? Will Express allow me to use added features that this mic is supposed to come with??
Just to clarify, I'm looking for specifics, not 'one is better than the other'.