Two of my favorites.
they're different. keep in mind I'm untainted by the abilty to squat clean or perform even rudimentary Oly lifts adn I use both as accessory lifts for PL and strongman stuff, at which I am still a novice.
zerchers build mega starting strength, and stress the anterior and posterior chain similar to a hip belt squat but with way more core forcus..I do zerchers for abs. zerchers translate to deadlifts for me..if my zercher is going up, my box squat will be going up and my deadlift will be going up....a zercher feels like you're prying something up off the ground..like a tire.
front squats. front squats stress thoracic stabilty more than zerchers, you can get sloppy with a zercher, not much with a front squat. lighter weights are still challenging with a front squat. front squats translate into raw jumping, vertical power. taking a weight from a very deep position and exploding upward is the provance of the front squat. when my front squat goes up so does my back squat
my theory on front squats...if you can front squat a weight..you own that weight flat out. I can front squat in the 300-400 range....I know that I can lift close to a 300 sandbag, a 300 keg and a 300 stone once I get it into position. it's just a matter of establishing leverage and then jumping with it....for me, front squats build acceleration, zerchers build starting strength. that may be just my leverages but that's how it works for me.
no time you spend building either lift will be wasted. right now I'm taking time off of back squatting of any kind to work my front squat becuase I know it will pay off.