Haha, ya, my dad has a 2009 E-class AvantGarde and I honestly don't like the feel of it on the road. It's one heck of a luxury car tho. My only thing with it is that I'm a driver, and all that luxury I don't need yet. I'm still young! Plus the E does feel weighted down and the brake pedal is placed way too high for my liking. I'm sure a E63 will offer driver enthusiast what they need in both luxury and power.
I'm a S fan, I'd take a S, better still, a CL than the new 7series. Totally personal opinion of course.
I'd honestly would suggest a M5 or a S5 if your dad wants a nice interior saloon with a mean engine