I've had Blue, Brown, Black, and Red switches.
Blue switches (Audible, tactile, light) are my least favourite, mostly because I'm not a fan of the noise they make and I find them too light (some people love this noise; you'll have to try them out. To each his own, but I can't stand it and I don't recommend it if you have to share a house/close quarters with anyone). If you can find a razer blackwidow in a box store they have a cut-out on the box that lets you try out the keys (last time I checked), so feel free to give it a shot before you buy.
Blacks (linear, heavy) are my second least favourite. They are a linear switch (no tactile "bump") and require the most force per keystroke. You will feel your hands tire after extensive typing with them. Sure, you can get used to it, but unless you are normally very heavy-handed and have a tendency unintentionally mash every key around the intended key you wish to hit, I would just avoid these. People say they're good for gaming; to be honest, even just pressing the wasd cluster for extended periods of time will tire your fingers out much quicker and noticeably compared to other keyboards.
Browns (tactile, light) are my second favourite. Nice sound, nice and light, with a tactile "bump" in the keystroke. I like these, although I find they almost feel "crunchy", especially if you have a tendency to bottom-out on your keystrokes, as opposed to touch-typing.
Reds (linear light). These are by far my favourite. They share the nice light touch of the browns, but without the tactile "bump" that lends browns to feeling crunchy. Unlike blacks, these linear switches don't require nearly as much force to actuate. I find the sound of them bottoming out against pcb to be quite soothing, unlike the metallic sound of blues. Can't speak for the sound against a backplate though as I've only used them on my KBC Poker.
The above is mostly my own opinion. If you're seriously interested, you would do well to wander over to
Geekhack and
this guide for extensive (understatement) information about mechanical keyboards.