Macbook Pro or Dell XPS

Hi everyone, I'm new here (sorry if my english is not correct) and also in Unity. I'm hesitating in buying a macbook pro 13" (mid 2012) or a Dell XPS L502X for developing a college project. My current notebook has lower specs (Pentium P6200 2 gb ram) and I'd like to work comfortably with Unity. Although the Dell video specs seems to be better (nvidia gt 525), the mbp comes with the new HD 4000 that is near in performance to many dedicated video cards. In the other hand, I don't have any experience programming in Mac OS X so I don't know if is really better than Windows 7 (I use Ubuntu for programming). if there is no known issues on Mac OS X, I'd like to try the mbp, but.. it worths?