From talking with a patrol guy in terms of CA specifics on knives with spring mechanisms the difference is basically the emphasis on manual-assisted. A switchblade (worthless for real life stuff anyways) or an automatic knife requires no effort from the user to deploy the blade with the exception on a button/switch. Virtually all other "spring-assisted" knives that most of us here carry are manual-assisted knives, meaning you the user have the use manual force to push the blade/thumbstud out to engage the spring mechanism. Again, I'm no expert on the matter, but after talking with an officer whose booked in more knives than a Kershaw factory I have confidence in that information. I'm sure we have CA LFer here that can cite the specific legal-ese that spells it out.
A side-note, before back when I was a police property specialist, I'd always hear of veteran officers complain about either their FTO recruits or just new guys in general always entering/labeling any folding knife as a switchblade. Mainly because if it ever went to court the DA would be pissed that the charge was wrong due to the weapon not being illegal (regular manual folder).