What gpu is better?

[thegussbus]

building new pc
mobo- Gigabyte GA-Z87-HD3 ATX LGA1150 Motherboard
cpu- Intel Core i5-4670 3.4GHz Quad-Core Processor
what GPU should i get?
Gigabyte Radeon R9 270X 4GB WINDFORCE Video Card
or
SAPPHIRE DUAL-X 14-202-099 Radeon R9 280 3GB 384-Bit GDDR5 PCI Express 3.0 CrossFireX Support Video Card
WHICH ONE IS WORTH YOUR MONEY?

 

[lfkfkfkffs]

http://pcpartpicker.com/part/msi-video-card-r9280gaming3g is currently the best deal