All PRO keyboards that I know of have the power switch on the rear and use a high quality switch. It is the best place for it because the power plug (mains) come in there and the power suply is nearby, Typically when I have seen a power switch on the top panel (T2 of mine) I feel the power switch is not of the same quality as the one they use on the rear (because of lo0ks ??

When the switch is on the rear, once you know whee it is you can easly find it without looking at the back of the keyboard.
You just go there with your hand and...it's there. You do not have to look back there, actually see it to use it.

Lee