Welcome to the board guys!!
It seems carboys vs. plastic is a bit of a personal preference. Most starter kits come with plastic, as they are ceahper and easier to use.
Plastic fermenters have a tap at the bottonm that allow for easy bottling/racking, while carboy's have to be siphoned into another bottling container.
From what I hear, Carboy's are harder to clean (glass) but you have the benifit of seeing how your brew is going.
Carboy's have the 'fragile' factor, which can be a big concern!
As I'm only new to brewing (the reason why I set the forum up) I have only used plastic, I would be interested in hearing from some other more experienced members to see what they think.....