Xti is more useful than the TI, IMO. I have both.
The TI is very bit challenged compared, to say, the old Wave. Because LM put in the blade for the eyeglasses screwdriver - wasting a slot in my opinion - this thing NEEDS the bit carrier big time. However, carrying the bit carrier adds a lot of utility.
The scissors in the TI are about 2/3 the size of the ones in the old wave. While the new ones can cut all sorts of things per LM claim, the size is a big issue. Difficult to get leverage to cut stuff plus the blade length is just too short.
The cutting hook on the XTI, if sharpened, will do about 60% of what a scissors will. With a sharpened straight blade you can pick up another 30% or so. In carrying the XTI, I have found no problem not having the scissors and use the cutting hook much, much more than I thought I would.
The other advantage of the XTI is that you have two bit holders for driver bits meaning you have 4 bits available to you from those two drivers. This adds a ton more utility and gets this thing so it doesn't feel so bit challenged.
J.