

Actually, in the US the outlets are often wired with 1 leg, while giving 2 legs gets you back to 240v.
110 is probably better in terms of general safety (which is good because our houses are death traps), but it means when you do need power you need a special circuit.
We should have both more common, but the plugs are terrible (basically they turn the left prong 90 deg).
Amps are voltage over resistance (I = V/R), volts absolutely matter, the human body has a decent resistance and the higher voltage helps burn through that.