Unfortunately the dumbbells cause a lot of pain just getting them into position, I am fairly happy with the straight bar.Interestingly, there is not heaps of robust evidence for this, but this is well accepted in the lifting community. Not sure why, elite level trainers probably don't want to publish their 'secret' knowledge for the competition to use.
Some people are unfortunately predisposed to chronic use injurys, particularly supraspinatus impingement (not me), regardless of a low elbow position. Whilst for many chronic heavy lifters the AC joint appears to undergo degenerative changes (yes me ). Also dysfunction in the sternoclavicular joint is not uncommon, pain, popping, symptoms of sublaxation.
I prefer dumb bells aswell, mostly due to the greater range I can use, although I find them more dangerous without an experienced spotter.
I have no doubt that when I take some some goodies it should all work with the bar.
Maybe bodybuilding may be a bit of science but muscles should respond to brute force as well