I recently tried the BXPs and they squealed like hell when set up the same way as I was doing with the greens. I can't be bothered to fiddle with toe in of the pads so off the BXPs came after a few rides. It's time for me to stock up on the greens.
Fitted them to my Campag Chorus - which seem not to require any toe-in - and they did the same. However, it really WAS cured by toe-in immediately so don't let that put you off.
Suspect it's a combination of wearing in and alignment, as not a peep now after 400 miles.
My opinion versus the SR pads:
1. Seem less aggressive on the rims (seem to be wiping less 'metal' off of everything)
2. Outstanding under hard braking - tried on Boxhill yesterday - and the effort vs. stopping power is lower
3. And modulation is good. Slightly less 'bite' than SR pads, but a less 'wooden' feel