well if i understand what u mean...
plucking is a much more complex motion than pulling...when plucking, every joint in the finger is performing an action, and the entire finger tenses to build pressure before the release. but pulling, only one joint (the strongest one) is working, and the rest of the finger can stay relaxed. pulling also has a faster recovery, as you can (kind of) swing fluidly thru the string, as opposed to re-setting under the string. and yes it may seem slower at first but that's just because you're not used to it.
http://www.youtube.com/watch?v=3M2yi...eature=related
when you watch jaco play this, notice two things: 1) his left hand/arm is totally relaxed, it looks effortless. 2) his fingers are straight but loose; they actually bend backwards a bit at the tips before each release