I'm not going to go into the weaknesses of other PV's, but I DO own all (but one) of the feeders on the market (some in multiples) & the Monkeyboxx VV is my favorite device out of them all. It's a vaping monster, & although it's made of wood, it's super strong. (I've dropped mine more than once & the batts didn't even come loose.) The MB actually weighs less than the Provari with an 18650 & extension. It's customizable to the buyer's preferences, right down to the laser engraving. Tom will even paint the engraving. The VV is controlled by a switching regulator, which is 90%+ efficient vs a linear regulator which can be as low as 50% efficient.
It might not be everyone's cup of tea, but the MB VV kicks ...!