shifter mechanism is made of cheese*, how they passed the approval is beyond me.
*ratchets are plastic(!) and the metal dog pawl chews them in no time.
yup, they are proper shite. The part that wears first (in the ones that I have seen) looks like it came out of a Christmas cracker. No... that would be doing a disservice to Christmas crackers... If that was the full extent to it then it might be OK but
a) fragments of the wearing part get into the rest of the mechanism and the hard steel parts can suffer damage as a consequence.... and
b) the wearing part is riveted (not screwed) to the rest of the mechanism and cannot be replaced.
If you could replace the offending (plastic) part at regular intervals (once a year or once every six months if you do a lot of miles) then you might get a reasonable service life out of it. But noooo.... that would be too simple.
I have heard theories that the plastic part that wears
1) is made soft (and therefore more likely to wear) by the use of 'the wrong lubricant'. BTW seemingly Campag's idea of 'the right lubricant' is, er,
nothing 
thus confirming that they don't understand either 'weather' or 'riding your bike much'....
2) has been revised to be an 'improved plastic'. Well they are still wearing out prematurely (the shifters often last less long than, oooh, a chain does...) so I'm not buying it as a 'cure'.
To the above I'll add a little theory of my own which is that the worst troubles come when the shifter is used half-heartedly on shifts that let the spring pay the cable out. IIRC the wearing parts are the 'escapement' ones that control the shift; basically a plastic prong is meant to stop a toothed wheel from turning under derailleur spring tension, once the main index pawl (steel on steel) is released. This only stands a chance of working if it is fairly firmly used; any slippage knocks the tip off the prong and thereafter it is only a matter of time till it slips. Maybe you can delay the inevitable by being firm with the shifters (and maybe this is how they were operated on some kind of test rig...). The shifters which suffer worst are often triple front shifters, presumably because the mechanism travels a fair way when each shift is done and the mechanism can be spun up to some speed before it is meant to be stopped by the idiotic plastic prong.
Add in the PT bearing issues and the groupset has surprisingly little appeal to anyone who actually rides their bike very much. Shame really.
cheers
