Ducky's are awesome keyboards. Good choice. Really, the most important factor is the switches. The model is more a matter of preference.

Blues are tactile and clicky. What I mean by that is that you can feel a little "bump" and hear a click when the switch is actuated.

Browns are tactile, but not clicky. So you can still feel the "click" but you can't hear it. Much quieter.

Blacks and reds are neither tactile nor clicky. They are linear. They are smooth and quiet. Reds are really light, blacks are heavier, as in they take more force to press.

I have no trouble with blues for gaming, but the point at which they actuate, and the point at which they release are different, so some people find it's hard to double tap. If you're a gamer, that could be a concern. Many people swear by reds or blacks for gaming. If you're going to be typing a lot, I'd avoid blacks.

Another factor is backlighting. I believe Ducky Shine key caps are clear plastic, painted black (don't quote me on that). The paint could wear over time. The backlighting is cool though. On the Shine II at least, you can set which keys light up and which don't, which is kind of a cool feature for gaming. You can have just the WASD keys lit up for example.

If you have a computer store nearby that stocks mechanical keyboards, I would go and try some out. Or at least see if they have a switch tester. Something like this: http://www.keyboardco.com/keyboard_images/cherry_mx_switch_sampler_large.jpg

Do you have an NCIX near you? That's the only place around me that stocks mechanical keyboards and has them on display so you can try out different switches. It's nerd heaven.