Gaming laptops are nice because they are portable. However, they are not as powerful as gaming desktops because they must deal with power and heat limitations as well as physical size.
To get close to the level of a gaming desktop, you will need to generally spend twice as much on a gaming laptop. And gaming laptops cannot compete with a really highly gaming desktop. For example, the recently released desktop GTX 980 for laptops is a slightly slower version compared to GTX 980 dedicated graphic cards for desktop; I think I've read it has 95% performance of the GTX 980 dedicated GPU (which is really, really good). But there's the GTX 980 Ti and Titan X for desktop.