What are you cutting?
If it’s stone/brick/concrete there are several choices, but personally I don’t use anything other than diamond discs now. The best I’ve found are Marcrist, and I use the same discs on all building materials - brick, block, plaster, everything.
If it’s metal, then I think the type of disc, and even it’s grade, are more important than the maker (provided it’s one of the decent makers). I don’t use anything thicker than 1mm now (except on aluminium) and the old thick discs feel really primitive if I pick one up. I also find it’s worth getting discs suitable for cutting stainless. They cut stainless or mild, regular discs only cut mild.
I generally use Norton as I’ve found them consistent over the years and I trust them. I also like the way they clearly explain their grading (good, better, best). I’m currently running Norton Blue Fire Inox in my 4 1/2” Fein, which is pretty much a dedicated cut off tool, but even Norton”s cheaper “Neon” discs are o.k.
I’ve used Bosch and Makita discs too, and they’re also o.k. but I don’t reckon they cut like the Blue Fire’s. I flat out refuse to use crappy discs. It’s not just about cutting performance and disc life, but safety, and I don’t take chances with grinders.
I should add that I’m in the U.K. so the brands I may have available might be different to yours!