I use the Emcotec SPS. I use the 60 amp version. It handles spikes to 120 amps and has proven rock solid in all my planes. As Peter noted, it does fail ON, but only if it is already on, so in other words it will not shut off power if it fails in flight. However, and I have confirmed this with Emcotec, the only way that can happen is if there is a hard short in the device, which they have never seen. If it fails while off, it stays off so there is no chance of an accidental powering of the ESC.

I am also a big fan of their switches for the radio battery. No mechanical parts, solid state and actuated by a magnet.

I'm also a huge fan of the AP 45-amp Anderson Power Poles (APP). True, they are rated at 45 amps continuous, but they handle more than that easily. That 45 amp rating is at 600 volts as well, so they handle our application with ease. Plus you'll never have to worry about a cold solder joint ever again!! I can wire up a set of 2 5S packs in less than 3 or 4 minutes.

http://www.powerwerx.com/anderson-po...owerpole-sets/

http://www.powerwerx.com/techdata/PP45.pdf

http://www.youtube.com/watch?v=QeTTw9i8WEc