Tip-up is considered a faster draw, especially if you're a fan of reverse-grip styles (which Bob Taylor most certainly is).
The Sifu works very well in both forward and reverse.
An interesting factor here is that a reverse-grip snapopen is more reliable than a forward-grip snap. And since you don't know what range the assailant will be at when he begins the festivities, starting with a reverse-grip certainly has it's upside. What I mean is, if for some reason the baddie manages to get right close in your face and starts some sort of grapple routine, a reverse-grip knife is considered by many to be more useful than a forward grip. If the guy is a distance away and threatening you, doing a fast reverse-grip snapopen that's nice and clean is likely to make him think twice, otherwise if there's time you can do a rotation or just fight in the reverse.
Having said all that, I'm personally a forward-grip proponent, who prefers a "stay on the outside" approach. So I run clipless, with a homebrew sheath patterned after a typical 1911A1 holster, set up to do an initial draw into a forward grip. That's because I'm big, somewhat slow but have good reach - I don't want to "get inside and play fast" like a Bob Taylor would do from a reverse grip.
The Sifu can be used with either basic gameplan. The plan needs to be integrated with the initial draw and presentation.
Jim
[This message has been edited by Jim March (edited 07-02-2000).]