To ask this atall, you are probably considering gaming on a laptop vs on a desktop.
As much as the market is trying to peddle gaming laptops, just step back and look at the facts.
Youll get a crappy keyboard, tiny screen, pay twice the money and when it finally runs what you want. Its not really a mobile device anymore, due to low battery life, external keyboard, external screen.
Then again some people dont really have a choice, desktop could be stuck somewhere with kids or girlfriend next to it killing its usefull hours.