As previous reviewers have noted, Mission St. (aka Highway 1) is a very busy street and if you happen to get a room near the front of the property, street noise is likely to be a problem all night long. We read other reviews before we booked and we asked for, and received, a room at the back of the property and we didn't notice street noise at all.
Also, there was one tiny portion of wallpaper up by the ceiling that was starting to peel off, but that's not really too surprising in a moist coastal climate.
Friendly staff, very clean and comfortable room, nice hot tub. The bed was comfortable and everything looked very clean, including the carpet. The continental breakfast, which was included with the room price, was also pretty good and included hard boiled eggs, several varieties of cold cereal, instant oatmeal, several kinds of breads, waffles, coffee, tea, milk, two kinds of juice (orange and apple), and water. It was very close to the beach, surfing museum, wharf, and Boardwalk, and Roaring Camp Railroad was only a 15 minute drive away. We really liked Mission Inn and will definitely stay here again the next time we're in Santa Cruz.