Spyderco, Benchmade, ZT/Kershaw, Chris Reeve, CPK, Case, Buck, Protech, Mora, GEC, SAK, Busse(and Kin), CKF, WE, Kizer, Reate, Ontario, Lionsteel, Cold Steel, Esee, Hinderer, Kabar, Leatherman, ETC, ETC. I am tired of typing.
All countless custom and mid tech makers. Everyone has their own experiences that will agree, or disagree with others. Style, materials, Made in ???, price, hand made, etc. All that will make people differently about all the different knives.
Overall, I see a large majority of people like Spyderco, CRK, and SAK. Although CRK are not my favorite knives, they do make well made blades.