I started out as an Olympic lifter in my late teens and early 20's. I love the movements, although because of injuries (motorcycle accident related) I can no longer do them. I got quite proficient at the lifts, but never developed much mass as a result.
In actual fact, in the clean and press you are doing a 4 phase movement. Deadlift, power shrug (high pull), front squat then press. One of these 4 phases will be the limiting phase (probably the front squat or press), which means the other 3 will be performed at a much lower relative intensity. There would also be a concern about volume because not too many reps can be done with these types of movements due to the cardio vascular stress on the body.
All in all, if you compared the intensity of doing the 4 phases individually during the course of a weekly bodybuilding routine with the various movements done on different days, the volume and intensity would be much higher and provide a much superior mass building stimulus.
If I were to pick the single best mass builder in terms of how much muscle the movement stimulates (at high intensity), it would probably be a toss up between the bench press (shoulders, chest, triceps), the bent over row (lower and upper back) and the squat (quads, hams and glutes with lower and upper back stimulus). Perhaps in terms of muscle weight stimulated the squat could be the winner.
I know a lot of people consider the deadlift to be a serious contender, but I would put it in 4th place or perhaps 3rd place at best.