Both are good gaming systems, but the specs on the Sager are a bit better. I say go for the Sager if the warranty terms are ok. The Asus should have a 2 year global warranty, plus one accidental damage incident. If the Sager can match or beat that, go Sager all the way.
I don't believe that Accidental is covered in the Sager warranty. At least it wasn't for mine a few years ago. However, money saved on the Sager could go towards an extended warranty. I'm a fan of Sager, so my vote is for them.