More barnyard waste. (I am positive this would be ok with sydney) mcoine, for being around bikes as much as you say, it seem like you really in the dark. When an Alivio derailleur doesn't shift correctly, that is because it is an Alivio? WHat about when an XT derailleur doesn't shift correctly, what causes that.
I am not going to flame mcoine, but to anyone who is interested in the truth here now or in the future...I have used several derailleurs over the course of all my miles. I too, used to have derailleur envy and the first time i would have a bike shift improperly, i would just assume it was because it was cheaper.
Over the course of time i discovered this couldn't be farther from the truth. Alivio derailleurs work great. In fact a well adjusted Alivio derailleur is far superior to a poorly adjusted XTR. I presently have XT and LX on my two mountain bikes. I have Tiagra on my road bike.
I've also had Alivio and Acera. When adjusted correctly, i can't tell one ounce of difference in the way they shift.
NOTE: WHEN ADJUSTED CORRECTLY. I don't shift with my XT now and say, "wow, this is so much better." It isn't. Any current derailleur will shift fine if you set it up right.
Of course their are quality differences in between upper and lower end derailleurs but they are small. And they make no detectable difference in shifting if you ask me. For what it's worth, i've shifted a few thousand times so i probably know.
I expect my LX and XT derailleurs will last longer. I hope they do because they cost more. But not once have i ever noticed that they shifted better, than Alivio or Acera when all adjustments were proper.