you are correct, it is pure personal preference. Korean pros even use rubber domes. The choice of keyboard really doesn't have much direct impact on the performance of SC2 players. Whatever you can get used to will do the job.
This is true, anyone that tells you one switch is better than another without giving good logic is just trolling.
Blacks are not good for starcraft IMO because 200+ apm on higher force keys can cause pain problems. I was a semi-pro FPS player and do not see why people say blacks are good for FPS (I used rubber domes at the time), I think they just see it on that OCN guide and repeat it like parrots.
Blues, browns, ergo clears, and reds are all equal for gaming, it is just preference (dont let people tell you doubletaps are a problem, they are not). TLO has serious RSI problems and he uses a Steelseries with blacks, along with a terribly non-ergonomic mouse (razer deathadder), so make sure your devices are not going to hurt you, but from there it is ALL preference.
I get 45g using ripometer for browns, and ergo clears, you may not be doing it correctly if you are getting 55g for browns. The tactile bump is a small part of the force curve, so it should not effect your ripometer readings.