I think from a rescue point of view, early neutering is good, as it means that no one can 'forget' to get the kittens neutered at the right time, and no cat that leaves us can ever reproduce - but sadly our vets wont do it younger than 5 months.
I can't see why the BVS would be shocked at early neutering, even CP are acknowledging it now, and I know a rescue who have been doing it for about 15 years now with no probs, and there have been cats done for longer in the US, so there is the data available now to prove that it is safe. Most people who have had it done say that the cats bounce back a lot quicker than at 6 months old.
CC - it isn't unfair at all for breeders to neuter, and they will only do it on pet quality cats, which is how it should be, they are being responsible by making sure that only the top quality cats will be bred from - they wont neuter show or breed quality cats, but they will only go to very carefully vetted homes and they will charge more for their kittens.