Installed and noice. My local shop needs my support, so I decided to go with the SLX from them instead of the XT from an E-Vendor. (Hey...it's just a freakin' FD, right?)
I was using an m750 prior to that. The new '09 SLX is pretty slick and cool compared to the 2007 XT. It's mated to a 2005 LX shifter I've been moving from bike-build to bike-build since I bought my '05 HKEK from my LBS. I need to check out updated upper-end Shimano shifters now to see how much better they are. This FD / shifter combo has plenty of cage and overshift to easily and quietly get into gear and settle back to center to kill any annoying chain-rub when you don't want it.
-Wide link mechanism is stiffer. (who cares...but it's cool, I guess)
-The "multi-size" clamp shims on the new Gen FD's are all aluminum vs. the m750 which was basically plastic with an alu insert
-SLX has a more linear motion (cross-ways) than the more arc'd XT. (great for a 2-ring setup)
-limit screws are angled out...easier to hit with a philips
Over all I really couldn't give a rat's grass skirt about it b/c it's just a front derailleur...but it's cool to see the technology trickle down. Smoothest shifting FD I've owned to date.