All you have to do is rub your hand along the tread and you will feel the high and low transitions. This is the start of cupping which IMHO is the function of the tread pattern, in combination with the slightly harder compounds which make these PR2 tires last longer than other tires. Yes, front BT021's are noisy right out of the box as well, I'll never have those again for other reasons. All said, given the good wear and decent handling in the warmer temperatures, the PR2's are a decent choice and a personal preference. One can live with the noise as it is moderate in most cases. If you're mostly a slab rider, they are just fine. Keep the pressures up from day one and they will wear/cup less.
My personal preference now is the Z6 front (prefer it over the Z8 I just replaced), for superior stick in all conditions and reasonable wear. In cold conditions, the PR2's don't stick as well after half worn. Exalto on the rear this year, don't see me going to a rear MC tire for the forseeable future.