Both are great looking cars with good exterior and even better interior, but if i had to choose one, i would choose the CLS55 AMG, it has a lot more character ,aggressive exterior and it has much better handling than the E55.
E55 it is just clean and beastly! it looks mean and agressive like its going to bite your head off. the CLS doesnt really pull that look as much and those Brabus wheels they make it look even meaner.