If the Buck has what you want and need then go for it. The X-tract is a great tool.
The pliers are minimally useful when compared to a a full size multi. Although they are way more convenient to deploy than a crunch they are no where near as capable.
I used to EDC an X-Tract for half a year or so and it was ok for most jobs at hand.
The X-Tract Essential is in my metro EDC rotation, I find I don't really need pliers around school and the apartment.
If you normally EDC a multi in a sheath, the XTract carried in its sheath should work fine for you.
The blade is about the best I've seen on any multi.