Which laptop brand is better?

Dell, but you have to get one that is a gaming build.

For gaming I'd go with a Dell (Alienware) or ASUS. Both build solid gaming laptops.

Asus because they make gaming hardware. Dell buys hardware from Asus

First and foremost, if you intend to use a laptop for gaming, then you should be more concerned about the GPU in the laptop and not the laptop itself. Nevertheless, some laptops have built in onboard GPU. The ASUS probably be a suitable laptop to get. Try and ensure that the laptop have either AMD or NVIDIA graphics card with gaming functions.