The Advantage coated rotor line from ACDelco is priced VERY competitively on Amazon. The coating makes it much easier to install, as you don't have to waste time trying to remove it (and it doesn't goo up your hands). The coating is designed to make the rotor last longer (and look much better), by slowing down the start of rusting in the unswept areas like the fins & hub area--the pads will wear it off just fine where they need to. If you live in Road-salt areas like I do, this is a "must-have". [NOTE: ACDelco offers 4 different rotor lines (not including specialty) for GM vehicles: 1) GM/ACDelco Original Equipment [OE} Genuine Parts, which for many 2013 & up is ALSO Heat-treated with a Ferritic-Nitro-Carburizing [FNC] treatment that minimizes rust much better/longer. Part numbers all start with 177-xxxx {x represents the different numerals identifying the specific application/part}. Usually made in USA 2) ACDelco Gold/"black hat"/"Professional" rotors are sprayed with black coating, & made for ACDelco aftermarket by IBI/Raybestos. Part numbers are all like: 18Axxxx. 3) ACDelco Advantage or "Silver" rotors are the "value" or "economy" option. Made in China, uncoated, except for a layer of gooey stuff so it doesn't rust in the box, {that you have to clean off}. Part #s are all: 18AxxxxA [note A on end}. 4) ACDelco Advantage Coated rotors are the Advantage rotor with a gray coating. Still made in China, but I will tell you that I have professionally installed at least 300 of them in the last 5 years, and only had one (not a pair, just the one), that i had to warranty. The part #s are all: 18AxxxxAC [Advantage Coated]. I see all kinds of reviews where people mistake various ACDelco rotor product lines for OE, thinking they are what came from the GM Assembly Plants.
