R9 290 vs GTX 770

Hi, I currently own a Gigabyte GTX 770 2GB OC. MY friend has offered to sell me his Sapphire Tr-X R9 290. I can probably sell my 770 and use just that money to buy the R9 290 from my firend. How much of an upgrade would this be? I am planning to install a Kraken G10 braket on at some point soon. Would this still work okay? Thanks :)