Just a few things to add to Scarlet Red's post:
1) Cookiezi shouldn't really be used as a selling point for any piece of hardware. That guy can use even the objectively worst hardware and still be in the top 3 (case in point: that Freedom Dive FC using a keyboard with Kailh-made Razer Greens)
2) I wouldn't say MX Reds are the 'fastest', they're just the lightest to press. They do wonders for your stamina, but make it more difficult to type or play accurately (it takes some getting used to). I will say that they're the most common type among osu! players though.
3) MX Blues aren't really that hard to press. They do click, but I wouldn't say they'd be easier to tap lightly, as the force required to press the key drops significantly once you pass the actuation point, making it more difficult to control your finger after the switch actuates. Coupled with the fact that the tactile point actually moves upwards upon release, Blues (and Greens) require more finger movement for rapid keypresses when compared with any other switch, and because of this, I wouldn't recommend them for gaming. They're not bad for typing though. (LK2 Blues have the click but without the tactile release, which make them a lot better for gaming IMO)
4) MX Browns don't click. You can feel a soft bump at actuation (a la rubberdome), but otherwise they're about the same as Reds minus the accidental keypresses. Out of all of the Cherry MX offerings, I prefer the feel of these the most (although I'm still completely in love with my LK2 optical switches).
5) Greens are for
people with a fetish for clicky switches people who prefer the feel of old-school mechanical keyboards. I wouldn't recommend these for anything but typing. (also: these aren't exclusive to CM, but gaming brands are very unlikely to use them in their keyboards due to how stiff they are)
6) MX Speeds are literally just MX Reds with a higher actuation point and covered with all sorts of marketing sensationalization. I don't see any problems with the switch itself, and I'd probably even recommend them over Reds if it weren't for the Corsair exclusivity and premium price point. I still think optical or capacitive switches would be just as good (if not better) though.
7) You forgot about MX Blacks. While they are stiffer than the more popular offerings, there are a couple of osu! players that swear by them. The stiffer spring provides a stronger restoring force, meaning that it takes slightly less effort to release the keys compared to the other switches (more effort to press down though). If you have strong fingers, they could have more potential for speed than Reds.
But yeah, as I mentioned, there
are other options for switches. A4Tech's optical switches are both pretty great (LK2 Blue switches are
miles better than MX Blues TBH), Gateron has smoother feels (despite technically being Cherry knockoffs), and Omron's Romer-G switches are somewhat unique and may be worth trying out (if it weren't for the high prices of Logitech keyboards
). There are also quite a few...cheaper Cherry knockoffs out there, but I'd rather not give those a try so your mileage may vary.
(oh, and if it wasn't already obvious, I totally recommend A4Tech's Bloody LK2 switches. A little birdie told me that the keyboards are coming stateside in September, so look out for those. Not sure about pricing though, but I imported a B830 TKL from China for about US$60 + US$40 shipping/import fees)