What you haven't told us is where/who you plan on buying this from and what the full component listing is.
Having said that Sager has a better cooling system than ASUS but ASUS tends to be a little cheaper on pricing. Assuming we are talking about stock configs the Sager is going to be better performance via components alone. Not by huge amounts but enough to say it is better. I'd go with the Sager if you can afford it. And buy it from someone like XoticPC, PCTorque, GenTech, etc., They'll have the better customer service than the parent manufacturers whichever you choose.
Just my 2 coppers anyway.
-Tt Overseer RI BLK case, 4790k, Hyper 212 Evo hsf, Asus Z97 WS mobo, 16GB RAM, Two Sapphire 290x Tri-X OC CF GPUs, 1TB Samsung 840 EVO SSD, 2TB WD Black HDD, EVGA Supernova G2 1300w PSU, LG 34UM95 3440x1440 Monitor
-Lian-Li V354, 4-Noctua NF-P12 120mm fans, ASUS P8P67-M Pro, 8GB GSkill RAM, Intel i5 2500K, Corsair H50, WD Black 1TB HDD, Optiarch Slim ODD, ATI 6950, Corsair HX850w, W7 Pro 64, Logitech G5, Saitek Eclipse II, I-INC 28" 1900x1200 LCD