I was informed that Norton norzon abrasive disks for 4" and 4-1/2" angle grinders were much better than most other brands. I decided to treat myself to a good quality product for a change and bought some. They do seem somewhat better than the cheap abrasive disks I'm used to, but whether I'd rate them as "much better" is uncertain.
At the college welding shop where I have taught or assisted with a class for many years, we have used Sait brand and some other undoubtedly overpriced brand which I can't remember the name of for our series of 14" chop saws (they don't last too long at a school shop). At home, I've used Harbor Freight's Chinese made and Russian made 14" blades, and Hitachi blades which came with a Milwaukee chop saw I bought. Frankly, I haven't been able to tell enough difference to matter. They don't cost much, and all of them seem to last a good amount of time. One of the brands at the college a few years ago wouldn't work unless you put a paper disk between the blade and the large hold down washer. We could get the paper disks from our supplier if we could remember to ask, or we could cut our own with scissors. Whenever someone who didn't know the secret would change a blade, the saw wouldn't cut. Those might have been one batch of the Sait brand, but I'm not sure. (What good is a lot of experience if you have a bad memory?)