Out of green/clear/red/black/brown/blue, black's are the harder to press individually, in my opinion, even though they are technically lighter then green/clear's etc, they are pretty hard to push down (I say individually, because testing the switches on an actual keyboard is pretty different)
Red's are beautiful switches, yet if you rest your fingers on the keyboard, you will press and activate them easily, without noticing, they even activate when you look at the keys the wrong way
My .02
Get black's if you type with 2 fingers, get red's if you are a master typist and type with 10 fingers without even resting your fingers on the keyboard
If you type with 2 fingers mainly, harder switches are very rewarding and fun