Elec or Mech Speedo?

I've noticed a number of folks are using elec speedometers when the go aftermarket. I'm sure there is a good reason, I just don't know what it is. Can anyone enlighten me? I know that the mech speedo is less $ which is good. I'm looking into Auto Meter Ultra Lites. Is Jegs/Summit the best place to buy based on $$?
 
Running wires is easier and you don't have to worry about kinking your cable too much or the cable melting on your headers.

+1 on the easy calibration.

-1 on the extra cost, especially if you have to buy the ~$65 mech to electronic signal converter.

All that said I've opted to go electronic with my new gauges... My $.02