is it worth to change slx 2011 rear derailleur for xtr 2009? I bought a bicycle last summer a Specialized camber comp and it mounts Shimano SLX as rear derailleur. My intention is to change it for a xtr derailleur (from 2009) which is mounted in a bicycle I barely use, the derailleur is as new.

do you think is worth to swap them? I am also planing to change the alivio shifters for a better ones since I think the whole set won't be balanced.
In my experience, the differences should be so small that I wouldn't botter the trouble just for the sake of change.

But, if you have a GOOD REASON (noticeable performance or weight difference for intended use), then XTR, even 2009, should be better than a brand new XT, although I think both are very nice - to the point you cannot tell the difference if you couldn't look at them or know which is which while riding.

In the end, personal taste and preference would determine the best option, I think.