a warped rotor has a rhythmic wow-wow feel while braking.
Juddered rotors with brake material on them just feel rough, shaking, but not rhythmic.
Re-bedding the brakes ( 10 quick 70 to 0 stops back to back) can clean up juddered rotors in most cases.
2011 e92 M3 Monte Carlo Blue ESS 535 - gone but not forgotten
2015 cayman GTS - new toy
2006 SLK 55 AMG sold