Congrats, you are in the minority. I saw 10 of them returned in six months at the shop I worked at. Never one Nanolux or Energystation.
We never moved a lot of the Solis Tek ballasts, but they work great and the one guy I know that runs them likes them.
I run ballasts with fans and just keep them in a clean area. I thinking about throwing them in a box with a booster fan pulling air out of said box and a furnace filter as the intake.
Either way, if a sealed ballast does ever fail, its junk to me. If one with a fan goes I can bust out the multimeter and see if its worth fixing.
To each their own, and whatnot.
(Please only use UL listed equipment. Especially if you grow in the house your family sleeps in.)