I bought my steelseries 6gv2 with black switches without trying any of them, because it's hard to find mechanical keyboards in my country. I got it because I mainly play BF3, so I thought it would be a good idea. And omg, I love this ****er here. It's so good for playing games AND typing, imo. I read a lot about the four main switches, and blacks were said to give fatigue. That's true on the first three days, then it's gone, at least for me. I can type for hours and hours just fine with this keyboard.
Bought a MX Blue keychain some days ago, looking forward to try it. I don't have any interest in reds, because I think they are too light and now that I'm used to blacks, it would be a horrible experience. And browns seems nice, but meh, I think only blues have true feedback.