I take offense to that!
Eldar are pretty good at melee combat; they are good at throwing punches and going first, but they rarely do damage and can't take a punch to save their lives. Wraith units are OK due to their beast statline, but still not great. Our dedicated assault units are pretty garbage.
Deamonetts are quite deadly against just about anything eldar, as they go before most space elves and rend aspect warriors, wraiths and armor all the same. Demons also negate the pseudo-rending BlaxicanX mentioned, as a 5++ does not give a damn about your
AP.
MC's are usually easy to drop due to pseudorending, but once your in melee your going to turn eldar into paste.
Eldar will also have a ton of S6 shooting. Most of their heavy
AT is either S10, melta, lance or haywire so heavy armor is probably not your best bed.