FLHomegrown

I have no experience with hydraulic brakes, so I am looking for opinions/experience with these. I have been very happy with my XTR shifting/ with my XTR rear derailleur...should I just add the Avid BB7 with ultimate levers...or would the XT hydraulics/shifters be an upgrade...or not? (I have heard mixed reviews on the shifter/brake unit)

Raiyn

Standard answer reposted yet again:
The Avid BB7 is sufficient for what 95% of the riders do on a regular basis. I have never been disappointed with the braking power or modulation. Smoothness and control are functions of lever choice and cable selection. With the right selection they can even rival hydraulics.
Pair them up with a set of Avid levers (such as the FR-5 which is specifically designed for the Ball Bearing Disc) and a set of Dry Cables and you're golden.
In terms of ease of maintenance the Avid's are second to NONE. The adjustment knobs give you superior "no tool" tunablilty. as a bonus cable brakes are also easier to work on in terms of "in the field" repairs owing to the fact that you can easily get a replacement cable and / or lever at any Mom and Pop bike shop (heck you could go to K-mart and get parts that would work to get you back on the trail that day.)

Who wants to mess with brake fluid in the boonies?

Hopper

Hydraulic XT brakes fell very very good, I have never used them in a dual set up (I have used Saint Hydro's which are the same). However for XC there is no advantage in going for th Hydro's over cable brakes. I would personally use the Avids as it will be cheaper as you already have an XTR shifter and only need to buy the breaks as opposed to shifter combo and Hydro brake.