I have experienced the same thing although not as dramatically as you describe. My brakes will squeal when the disc brakes are applied as I nearly come to a stop. Quite annoying as my $42,000 car sounds like an old clunker when I pull in my driveway. I've gotten good at using the regen braking almost exclusively so I will try, as Henry suggested, a couple of hard stops to clean up the discs and see what happens.
The feeling in pedal is just a feature of the braking system and one valid criticism of the Volt in that the transition from regen to hydraulics can result in a suddenly more aggressive stop. Just takes some getting used to, especially going into a hard corner.
That's not a knock, believe me. I love my Volt.
2012 Volt #C3565
Silver Ice Metallic
Jet Black Seats/Black Accents
Arrived home in Phoenix, AZ on 10/6/2011