My front 'Stone would howl about 16k. I think she was saying "please replace soon!"
But since the Traxxion upgrade - my tire wear has been so even that I don't get the howling anymore.
Avons & Metzler seem to be the tertiary choices after Bridgestone & E4.
They are both a softer compound and may not wear as long as the other 2, but in the "smiles per miles" category" they'll get you grinning!
Cheers,
Steve