The specs look good. It's got the same graphics card as the Alienware M14X, so games should play well on it. The high resolution screen is also nice to have, as are the USB 3.0 ports.
As to its portability, it's a decent weight for a 15" notebook. If you haven't used a system with a 15.6" screen, you can get an idea of their size and weight by going to a local computer or electronics store and lifting a few. In my opinion, that size is moderately portable, but if you plan to be taking it on a lot of airline flights, I'd go with something a bit smaller.