They're nice, we have one and use it for a lot of different things especially filling bunkers since you cant see well around blades.  Ours is a Wacker LTC-4. You'll spend more than that to get a semi decent one. 

They make electricity to run lights and maybe one other little thing, if you want a genset buy a genset.  There are towers that have excess capacity but they cost more.  IIRC ours is rated at all of 12hp and uses 0.4gpm at max load.  They'll run for days on the fuel they hold. The rating for light is around 7 acres but all depends on how you aim them and how much light you need.

It does make things much safer in busy areas like bunkers.