The trick with steering head bearings is to replace ALL the loose balls AND the races at the same time, or convert to tapered roller bearings (moose or all balls racing are both decent kits). Use the best EP grease you can get your hands on, and adjust them correctly with a little bit of preload (any play is bad). This will all make way more of a difference than the name brand of the bearing. Same goes for wheel bearings- good grease, and make sure the spacer in between the bearings isn't worn, that will affect the preload on the bearings. Follow those recommendations, and keep the pressure washer nozzle away from them when cleaning, and they'll last for years.
1985 Tri-Z 250
1985 ATC250R