The performance of any keyboard that uses a standard layout like that of the Rosewill RK-9xxx series keyboards is largely defined by the key mechanisms used. Rosewill produces the RK-9100 with different Cherry MX switches that are still in production. The one we got had the Blue switches installed; they are mostly geared towards typing but can, of course, be used for gaming. The Cherry MX Red and Black switches produce the most ideal key mechanisms for gaming. The Black switches have a very high actuation force and the Reds have about the same as the Browns. The Browns are a good hybrid with non-linear feedback, perfect for a keyboard that will see equal amounts of typing and gaming. This is, naturally, largely up to personal preference, so try them out before making a decision if you have the opportunity to.
Typing
Typing performance of the Cherry MX Blue keys is still very impressive; it just feels so right typing on a keyboard decked out with Blue switches. It is even better than on Browns, but the annoying click sound is just unbearable. The noise level of the Blue switches is a real pain in the you know where. Their greater typing efficiency is largely due to the click-release mechanism that produces all the noise since Blues are essentially Reds with click-type tactical feedback. Fatigue-wise, the Blues are preferable, but they are problematic in gaming scenarios where clicks in fast succession are required. Double tapping is impossible with these keys.
Gaming
Gaming with the keyboard was good but somewhat compromised by the use of Blue switches. Fortunately, you can get this keyboard with most of the available Cherry MX switches, which allows you to get it just the way you like it. Personally, I prefer Browns or Reds for gaming, but some might like the Black's very high actuation force as that reduces the amount of accidental strikes.
If you change modes to where nothing but the WASD area and the arrow keys are lit, the keyboard automatically disables the Windows keys, which is great for gaming. This is, besides the lights, the only real gaming feature of the keyboard since Rosewill does not supply a gaming-geared driver for this keyboard.