The Electrogen puts out a dry fog, you can test it yourself with a piece of cardboard. The ULV's still have their place, partially because then do produce a wetter fog. That can come in handy when you want to send small wet droplets under velocity.
Most of the time I prefer the dry fog because there is more room for error, less chance of moisture falling on the wrong surfaces.
While I would wear a respirator while using either, the ULV's will make you choke if you don't.