Which one is better? Lenovo Y510P or Asus G56JR?

How often should a y510 battery be replaced? Such as: http://www.cbatterie.com/lenovo-ideapad-y510p-batterie.html.

Both of them are a great laptop.

Y510p allows you to replace your optical drive for another GPU or video card to make it SLI with the one that is currently inside of the laptop.
It is definitely powerful, but you also increase the heat and lower the battery life.
My complaint with Lenovo Y series laptop in general are the touchpad. It is integrated, and it is horrible.

Asus G56JR is also a good laptop that has a really good cooling.
Now, you don't have an ability to replace your optical drive for another GPU or video card.

Now, it really depend if you would prefer a gaming laptop that doesn't need to do SLI and perform straight off the laptop with a decent performance while maintaining a good cooling.
Or you want a laptop that allows you to add a second video card or GPU to perform SLI, and it exceed some or most (last gen) laptop performance, however, you also increase the heat.

Lenovo Y510P