well, asthetics aside, shoplights use cheap ballasts ... either magnetic which are decently efficient (in terms of energy usage, not light output), or low-end electronic which are inefficient in light output and enery usage ... and usually the have a hum to them as well
hellolights, ahsupply and other use high-quality electronic ballasts, which operate at a very high frequency (eliminates hum and makes the bulbs brighter) and are very efficient in terms of energy usage and light output
you could use the shoplight as a bulb holder (gets you the sockets, wire, chassis, etc), and then wire in your own ballast, which will get you more light, less noise and some energy savings.
ge and sylvania both make fairly efficient and realitively inexpensive electronic ballasts that you can get at HD or Lowes, but those ballasts still don't match the output of something like an IceCap or Workhorse