Wow good choice with the Sager laptop! I have 2 Asus G1s laptops and they have weak GPU chip sets. Its been a headache to send one of them out for repair. I like the Sager over the Asus because of the separate user upgradable graphics card.
I think the G53 is a very stable laptop, but I would go with Sager.
what games are you going to be playing think if you really need the way better graphics card from Sager. The ASUS can easily play BF3 on High. The ASUS has away better design and a backlit keyboard the Sager does not. The ASUS seems better for your buck but the Sager had awesome interior but the design sucks. I do not know dude good luck finding an awesome gaming laptop.