questions for graphics cards?

[Tyler]

What is the good side and the bad side about sli and crossfire? I'm trying to get either a EVGA GeForce GTX 760 2GB GDDR5 Dual Superclocked Graphics Card with ACX Cooler or a MSI NVIDIA GeForce GTX 760 2GB GDDR5 Video Card with Twin Frozr Cooling Fan and OC Mode which one is better? or should i just go for a different graphics card? amd vs nvidia which is better? I know they both probably have good things of their own which probably make them equally good. but advantage will i get if i go nvidia? or amd? im planning of getting 3 monitors total to have surround. please give me some answers for my Q's i would appreciate it. thanks!
CPU: Intel Core i5-4670K Haswell 3.4GHz LGA 1150 84W Quad-Core Motherboard: GIGABYTE GA-Z87X-UD3H LGA 1150 Intel Z87 Memory: G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1866