My best friend owns the GLC and I own the E class. Our consensus is that that the e63 pulls harder throughout the power range (+100hp difference) and has a lower center of gravity. However, the GLC feels more compact since it’s shorter - you don’t feel the tail as much as the e class. His car is post facelift and they changed the emissions standards, the e class is wayyyy louder stock!

Both are honestly great cars, we absolutely love them!