Another bassist to watch who doesn't look like he's moving that fast is Victor Wooten. I doubt anyone would say he can't play fast and his technique is good. Oddly enough, for the up/down plucking, he only seems to do that with his thumb, never with any of his other fingers. But he is excellent at inserting open strings, strums, and taps.
mmmm.. i really think it`s up to u as a player.. 3 fingers are faster.. but u have to remeber that technique is great more for triol-notes (i don`t know how u US call those 3notes with thick line connectec eachother) but not that great for straight notes like 16th or somethi8ng like that... i use 2 fingers when i want/need/etc. 3, when i want to be specificly fast i do 3 fings or slap or tap or i try to make up some new bull**** (mix of all those stupid things)....
i do not think u really need it but u can also miss it.. if u really like a bassplaying better to learn it and see what everything u can do with that...
(I LIKE IT A LOT ;-) no matter that i am not queen of 3fingerstyle)
Les Claypool was quoted as saying he knew he was a decent bass player once he could pull off "Roundabout" all the way through. Nice song that works on not only speed but a consistent rhythm. "Parallel Universe" is a good one too for the same reason.
Playing fast altogether isn't too difficult. The real trick is keeping it up for more than five seconds and making the rhythm consistent.
One crucial key to making good music is to not play too much, only what the song needs. We are here to make sounds enjoyable to listen to, not win finger-style sprints (if that was the case, Victor Wooten would have taken the prize a long time ago).
Look at John Myung on the TOkyo video.. and watch his Progressive Bass video.. 3 fingers is the way to go, not only for triplets. 
