This is an interesting question. Back the mid 70s when I first took up the hobby, auto kits were dominated by Mongram (remember those cool Tom Daniels Design kits?), AMT, MPC, and Revell. Maybe an occasional Lindbergh kit too. Aircraft and armor were Monogram mostly and Revell. All were great kits in that time.
Fast forward to early 80s after I graduated from high school. I discovered a hobby shop downtown so one day, I decided to check it out. I was like a kid in a candy store. There were Hasegawa, Fujini, Italeri, Tamiya and others in aircraft, ships, and armor kits besides the usual Revell and Monogram I was used to buying. That day, I bought my first Hasegawa kit. I was hooked on the brand. Then Fujimi and Tamiya followed.
So the question begs which brand do I choose over others? I don't because it all depends on the subject. For auto kits, I will choose AMT or mpc because I've always liked the option to build in different versions - be it custom, stock or drag. I like to mix it up if possible.
Aircraft - I will choose Hasegawa, Fujimi, Tamiya , Airfix, or whatever brand to my liking. Again, it depends on the type and decal options. With so many aftermarket stuff out there - especially decals, it really doesn't matter what brand I get. I will research and read kit reviews of a particular aircraft kit brand for fit issues, inaccuracies, or whatnot.
Armor and ships I don't really get into those much. I've done them but the mood to do one are rare.