Members of Congress receive the same ho-hum benefit package options that every other Federal Employee recieves. It amounts to the same thing as many employees of large corporations get.

Several years ago (like pre-1990) they had some additional benefits, but those are long gone. Their retirement plan may be slightly better than most, and it takes a far shorter period to become vested for a pension than is typically required of most positions, but that is about it for "preferred" benefits.