I upgraded from integration 6800 to 8000 when my old 6800 FD broke.
It was a great decision. The 8000 is so much more adjustable and manages the cable. Instead of having to fix the the cable just right to keep it from rubbing on your tire, the new model has a plastic cap which routes the cable backwards in a reliable way.
The auto tension is the other big change. After fixing the cable you tune up the cable tightness with a few turns of an Allen key. So much easier.
This is by far the best front derailleur I've ever used. Shifts are lightening fast, silky smooth, and absolutely reliable. It was a little tricky to cable -- after passing through the pinch bolt, the cable wraps around the front of the housing then passes through the protective cap and back toward the rear wheel -- but once I figured out the cabling and adjusted the stops, it works great. Shifting is effortless and precise, and the price was very reasonable given the derailleur's quality. I highly recommend this derailleur. Get it -- you won't regret it!