for the money, I think one of the best things you can do in planes that size is just run a parallel battery system. Two 5-cell packs, two conventional switches, each plugged into a separate channel on the RX. Use gold plated connectors on everything, and use a voltmeter before each flight. Check each battery separately. I turn on one, check the controls, turn the second on, and the first off, and check again, then turn both on and go fly. The odds of having 2 switches or batteries fail on the same flight is remote.

Even with any of the electronic switches, you still have several places where a single failure will cause loss of the model, the electronics in the switch can fail, the battery can fail, a connector can fail, etc.