ideal gaming laptop when comes to performance on a reasonable price  

You clearly don't want Alienware.

Yes, I know, they claim top notch performance, they do have a good look, probably even have some stuff overclocked and whatnot, but if what you have to concern is price, then you could probably shift all that money you'd lose to buying a brand to actually buying a laptop with proper equipment and still come out winning.

You'll have to look at the specifications above all. If the CPU is A or B, if you have C or D GBs of RAM, what kind of hard drive, if the graphics card is E or F and how much dedicated memory it has.

All those things count, much, much more than if it is Alienware, Dell or Asus.
Acer for example is a reasonable brand, offers a wide array of choices and they surely have machines that can fit the gaming field.

You'll want a good CPU, a sizable amount of RAM, a decent hard disk and of course the best VGA you could have in a laptop.
You probably won't need any Blue-ray readers or anything so you can take that off of your search list.

I guess this is kind of vague since I'm not offering you any model suggestions, but, first of all I'd just like to know if you must exclusively buy one of those more well known brand machines.