It is really fantastic and is quiet all things considered. I ended up taking an old leftover tube cover and cut the inner spring down and it's also shields the electrolytics from any heat.Those holes make it look badass. Mine doesn't get overly warm but I did think about giving it some ventilation as I was putting it together. I ran it pretty hard on the bench before I boxed it so didn't end up doing it.
I definitely would power it down when with the rest of your board when you walk away from it but that's true of the board in general. This has become a permanent fixture on mine and I'm using it as a low gain boost. Coupled with a Dead End FX's Terrahawk it's just a silly flexible combo.