On the front, WHO CARES!!! IMHO, front derailleurs of ANY make/quality/price are virtually identical. They either work or they don't. If it works, it's as good as anything else.

REAR derailleurs, on the other hand, seem to improve with price. I think it's the closer tolerances and better design, but I'm just speculating. I do know that I can tell the difference between my XTR and an LX just by the way they shift.

Live with the front so long as it works. When it dies, buy a Campy Record off e-Bay for $20 and you'll be set.