I've been running Zillas on my old '95 TRX300FW for about three years now, and I'm very impressed with them in pretty much all aspects. Traction is great, they ride smoothly, lots and lots of flex (even at 6-7psi), they're very lightweight, and they're wearing significantly better than I expected. All of my riding is in central WV, primarily on logging trails (from so old you can barely see them, to just skidded) with a lot of rocks, mud, leaves, broken limbs and branches and downed trees. For as mud-oriented as Zillas look, they actually make very good all-around tires, and tend to not be too destructive if you're riding around in the front yard (vs my Executioners, which seem to have confused themselves as rototillers).
I was also going to pick up a set of Zillas for my '17 Rubicon, but decided to go with Kenda Executioners instead. Due to a quirk of online inventory management and shipping, I wound up with a full set of both 27" Zillas (27x11 and 27x9) and Executioners (27x12 and 27x10). The Executioners are definitely much heavier than the Zillas (as well as being taller), but so far I haven't had any problems spinning them. Even long hauls up very steep power lines with 200-300 pounds of corn on the back and 270kbs of me on the seat, the Rubicon isn't bothered at all in high range (although I don't do the "bury the fourwheeler to the handlebars in mud" stuff, so I can't comment on that aspect). I didn't think to get a weight before I sent them back, but the Zillas felt very close to the same weight as the stock tires - I would think no less than 2-3lbs per tire heavier. Executioners are something like...34lbs for 27x12s, I think.