I've had an evolution of thought over the years about using heavy dumbbells for pressing movements, both chest and shoulder. The shoulder training clip I just posted on my new YouTube page brought it to mind so I thought I would share it.
Though dumbbell movements are an excellent compound choice of exercise and they fit squarely within the Max-OT principles I feel there is a diminishing return using them, particularly when you develop a level of strength forcing you to wrestle with the big boy dumbbells at the end of the wrack in order to get enough resistance. At that point I think you are better off sticking with barbell movements.
There is a lot of wasted energy before you even start the set as you can see from the clip. This is true even if you have a partner handing you one of the dumbbells. It's even worse if you are trying it on your own.
Not only do you waste energy getting in and out of the exercise, you also potentially place yourself at a higher risk of injury in my opinion because you can end up in some compromising positions that are placing undue stress on your body.
My advice is load up the bar and focus all your energy on moving the weight from point A to point B.