I'm not saying they don't work, of course they do. But if as Pud237 says, "as Alfa Engineers want them" - I am presuming from this he means the manufacturers - why don't they fit them as standard. Plenty of feedback is given to Alfa, just as it is to VAG, BMW and Mecedes, upon which they are only too willing to investigate and modify accordingly. So why are Alfa so steadfast on this issue? It is true, OM bushes have a hard life, and I am on my third set of top and bottom front suspension arms, at 132,000+ on the GT. But the backs have never been changed. I spent 14 years commuting 80 mile a day, across East Anglian roads, so I accept there will be a little more wear due to the B roads I used. But I maintain, for optimum road use, standard bushes are fine. Optimum being the key word, balancing between extremes. I just think, Poly-bushes are fine for tracks, but not the kind of roads I use. And I re-iterate, the inertia has to go somewhere, and if the bushes won't absorb it, the rest of the mechanicals will. Still, I'm glad you haven't had any major failings.
Everything is a compromise. Alfa's compromise is to use voided rubber bushes which offer much flex, still use agressive toe-out settings and tyres are scrubbed on the inner edges after 6,000 miles. But the car turns well, and there is very little road noise.
The person who doesn't care much about how the car feel's to drive, their compromise is just to re-align the car to 0 toe and get much better tyre life, and put up with the soggy handling and lifeless steering that creates.
I personally think the best compromise is to Powerflex the lower wishbone rear bushes, which improve steering feel and tyre life at the same time while retaining Alfa's specified alignment settings, at the expense of a bit of road noise and some additional firmness over broken surfaces.