The Catalina Express has really improved over the years... Not that it was ever bad, but today the ride seems smoother and definitely faster than it used to be. (Even the food at the snack bar at the Long Beach terminal has improved ... We were surprised at how good their hamburgers are!)
I should add that we went in December, right before Christmas, so there were no crowds, the line to board wasn't long, and we pretty much had our pick of seats. So I don't know what the summertime experience would be. But in December the experience was very enjoyable: friendly crew, clean vessel, smooth ride, quick trip.