Mechanical keyboard have different swith which require different strength to press.  Refer 1st page for different type of switch
So far from among user experience Cherry MX Red give softer experience compare other switch but this is depend on user one. Black switch is harder one but still a lot of user feel comfortable with it

regular membrane used around 55g +- depend of design. But advance of mechanical keyboard is it fast activate compare to membrane because membrane u need press till btm only the key will activate but mechanical switch not need to btm up also will activate already you press like 2mm like that only, so when u 1st time used it with membrane typing style you will feel tired cause u will auto keep btm it but when u already get used to it, u will  auto not to btm it and make typing very comfort already.

Like me i am black switch user, when i 1st time used my Keyboard is like typing machine cause i keep btm it and finger feel very tired after some time. After few month of using, currently i type with less btm it already which make my keyboard have less sound already compare to first time used. The 1st part u find the different of mechanical keyboard will be the part where the key return to it position after press is very quick/solid compare to membrane.
Not sure about other but that my 1st experience when i start used.