Strafe is pretty much just as good as the K70. Unless you're really looking for the aluminum chassis, I can't justify the cost difference of switching to a K70 Lux.
The quality of switches are the same, they have the same lighting controller, and the only real difference is an aluminum chassis. That's up to you. Both are fairly durable at any rate. The Strafe RGB looks a little better simply because they use a white backplate on a plastic chassis, compared to the K70 LUX which is just pure aluminum chassis.