So I'm guessing that you are talking about Visual Studio?  It's a whole lot more than just a text editor that uses the command-line compilers.  Intellisense, debugging (not just stopping at breakpoints, but attaching to running processes and interrogating objects), super integrated help....those are just the ones that come to mind off the top of my head.

I tried using a bunch of the free ones a year or so ago.  They were all nice, but nothing compared to VS.  You should check it out sometime if you get a chance.  If you are a student or know a student you should be able to track down a copy for $100.