Out of the two I would choose the Corsair. I own a Corsair K90 keyboard and it's really nice. I've had my share of Steel Series products and I've never been too impressed with them.
HOWEVER, I must admit that when it comes to mice, keyboards and headsets it's basically personal preference. It never hurts to own more than one nice keyboard 😀 I use a Corsair K90 and a Daskeyboard with blank keys, each are very nice in their own way.