I've got a G15 mk1 (blue), G15 mk2 (like sheps) and the G19 and frankly, once you've used a mechanical you'll never want to go back to rubber domes. The LCD panel isn't much use either in my opinion, even the G19 one is crap. Extra monitors are the way to go for displaying more information.
Nope, dead serious, In Arma 3 they sit at such low utilization (even with shadowplay and driving 6 monitors + streams etc) they dont go over 25% or so and their temps are typically at around 50c, which is below the 65c fan spin up speed.
My PSU has a similar passive-till-hot-enough setting and that doesn't spin up much either (that's due to the awesome efficieny of the 900 series) so the only thing I can hear if I listen for it most of the time is the CPU fans.