In my ham shack I mainly run the mfj 993b automatic antenna tuner. I did have the dreaded power button problem with it. After replacing it numerous times I replaced it with a toggle switch. I have not had a problem with it since then. It is a little tricky to take apart, but it can be done. I mounted the toggle switch in the lower right corner where there is just enough room.
I had to remove the current power button, which was not too difficult. Just have a good soldering iron. I would also recommend using a esd static wrist strap and a static mat. Make sure the mat is grounded properly. I used a digital volt-meter to determine which contacts to solder the two wires from the toggle switch to. There are some traces that are connected, so you want to make sure you don't short anything out.
That's really all there is to replacing the push button and replacing it with a toggle switch.