Costs a bit more, but I waited until a sale came along and used a gift card.

It allows me to have the dust collector out of the way on the other side of the garage, plugged in with no extension cord, and turn it on from anywhere I might be working. I went this way as some day I hope to have a more elaborate shop set up with a plumbed dust extraction system. This switch will allow me to turn on the collector regardless of which work station I'm using.
Another benefit is that I decide when the vacuum shuts off; it doesn't shut off as soon as the 520 is powered down. Sometimes I'll sand a piece on the 520 in lathe mode by hand, turning the spindle slowly. With the iSwitch there would be no vacuum. I can keep mine running and hopefully extract a bit more dust from the air.
Just thought I'd offer up another option.
