Enterprise offices vary in customer satisfaction. Speaking only as to the HB office, based upon my own experience and that of several of my acquaintances -- AVOID!
Enterprise HB is known for turning around cars without service or washing (sometimes within minutes of turn-in by the last customer) and almost always with practically NO gas. So your first stop has to be at a gas station. You also cannot rely on getting the category of vehicle you requested.
In addition to the Hertz office noted above, there is an Avis office also on Beach Blvd: 19092 Beach Blvd, Suite W Huntington Beach, CA, 92648 , US (1) 714-374-1977.