my sister used to have an SLK55 and it was fun. not for everyone though.
if you don't mind not having much cabin room, then i would say go for it. there werent much cons (in my opinion) aside that it's more common for girls to drive a SLK. then again SLK55 is a different story i guess. i'm 6'1 and it wasnt uncomfortable or anything. just felt a bit cloustrophobic at times.
thing has so much torque, i miss it. she has gotten an E63 since then.