I've never played the Rebel Yell, but I can't imagine they're very similar. Like was mentioned above, I too find the M6 to be a very unique and not highly versatile pickup . It punches hard with a big low end, prominent hard peak in the attack, and smooth mids that sit back. They can actually come off as being peaky and overly tight while simultaneously being boomy in the lows. I've had the M6 in a couple of different guitars - a neck-through Ibanez (alder body & maple neck) and a LP style guitar. Oddly enough, I liked it best in the LP-style guitar, which surprised me considering how much low end the pickups put out. Anyway, the eq & feel of the pickup really starts coming to life when you're boosting amps in a high gain setting as they retain enough heft in the lows and the hard prominent attack isn't overly softened or blurred after boosting. They certainly work without boosting. I really liked it straight through my EVH Stealth. But yeah, that's my take on them.