I'll break away with the pack and say I HATE KWA. Frequent failure of their 9mm bushings, glued-in shims/ unshimmable gears, proprietary hop up, gear axle placement is incorrect / not spec, lots of other complaints. Stock, they're more or less "OK" but if you want a gun to upgrade, seek elsewhere.
Techs mostly hate KWA, people who never have to work on their guns mostly like them until they fail.
I like TM & CA "proline", some G&P guns (mk23). Chinese guns: JG has pretty strong internals, but accuracy and consistency are places they need working on.