I put in a Korky Toilet Repair Platinum Complete Repair Kit (4010MH) as a trial a few months ago. It is working well and I recall has a 5 year warranty. There were a couple of quirks in the installation. It uses a universal tank to bowel gasket that was much too thick for my toilet. After struggling with it, including trying to cut it down, I finally replaced it with a thinner gasket intended for the Crane toilet that I have. It worked fine, but cost me an extra $5 over the "complete" kit price, and the time it took to pull the tank on and off a couple of extra times. They also have an interesting flush valve that requires adjustment to get the correct fill flow that slowed me down a bit. Once you have it set, then it works well. It claims to be quieter, but it is really is not significantly quieter than the original style of fill valve. It does fill more slowly though.
Despite the issues, I probably will continue to replace the parts in my other toilets with the Korky when they need it. Next time I will buy the right tank to bowel gasket and throw the Korky one away... And you could just install the fill valve assembly for about half the cost of the complete kit. It is nice to have the adjustable flush valve though. I think it alone could also be installed without the whole flush assembly.
