I have a K90 and love it. I would of bought a K60 as I don't use the macros on the K90 but I wanted a backlight.
in my local store they are within 10$ of each other im pretty sure
SteelSeries 6Gv2 or G7?
Find out what switches you want first, there's so many options these days.
What are the options for switches? Would want the best for gaming.
I'd go with a cm storm quick fire rapid with cherry blacks or browns