A lot depends on your climate - it can be very nice to have in a cold climate if you are having a tough time getting fuel to light off and the battery is cold. In a warm climate, probably not as much. I use my airplanes in varying climates, and would rather have jump capability and not need it than need it and not have it. I grew up where it was bitter cold and hangars weren't alwasy available - in that case, a jump can sometimes be priceless.
These can be installed without "an ugly wart on the outside of your plane" (sorry Bill) with a little ingenuity.
Right now, we have three planes - one with external jump capability, one with an internal cable connection for jumping, and one with just a hidden charger/maintenance plug. So we cover the gamut.