I used to game on a laptop but I don't anymore. When I noticed that my laptop was getting slow I just decided to go for a desktop. You can't upgrade a laptop and usually when I played games it got really hot in my lap. When laptops overheat they have to underclock which means a huge drop in FPS. If I had to go with a gaming laptop I would go for the alienware laptops.
I strongly recommend against Alienware. I had one and it was the biggest piece of garbage. It's currently sitting in my closet - a $2,000 brick. I had problems with it from day one, mostly display issues. It was supposed to be a top-of-the-line gaming powerhouse with dual GPUs and the works. I kept getting what I would call the "Green Screen of Death," where the entire screen would go green and black (not unlike the old MS-DOS systems back in the day).
When I tried to get support, I also got none. I happened to buy my system right at the wrong time. They were in the middle of the Alienware to Dell transition, and so the Alienware support center was shut down, and the Dell support center wouldn't support me.
After struggling on my own for months, the system eventually just died. It won't even power up anymore. I've never had a laptop brick as hard as this one.
Maybe I got a lemon, but I will never, ever use Alienware again.