well asrock from what i hear is just a terrible company.. but i have no first hand experience...
and crossfire is ati's sli.. basically it lets you use 2 ati graphics cards.. 1 crossfire edition card, and one regular card together connected with a dongle to give you awesome incredible performance!
Intel 3770k @ 4.4 GHZ | Galaxy GTX 770 SLi | 16 GB G.Skill Sniper | ASrock z77 Extreme4
2xSamung 840pro 128GB in Raid | 2x1TB Seagate | Antec 750 Watt GamerSeries
Intel Core i3 3220 | Galaxy GTX 650 | 8 GB Corsair Vengeance | ASrock B75M | Samsung 840 120GB