Sonic-wise the HD 518 are the way to go. Although i dont like the pads on these. Havent heard the SHP 9500 myself, but they seem to be a compentent performer. Ive read that the earpads, which are just glued on, can tear off easily and are not replacable. Thats actually a deal breaker for me. I love me some replacable parts and dont buy headphones anymore that are just a "one way ticket", so to speak.
Havent heard the CAD, but I own the HD 662 F and these can be very bright, too bright for some, but also very "airy" in a sense, because of that. The CAD look like HD 662 B though, so that might not be an issue.