Personaly i like to do them with DB's. I think that DB's hit more of the trap directley. BB tend to involve a lot of front delt and the shoulder is pulled forward. Plus i don't have to worry about my nuts gettin' in the way. Either way you gotta go heavy on them
I personally thinks its majorly just preference. I mean I personally prefer dumbbell shrugs because of the stretch and contraction along with the range of motion you can achieve. Many people prefer bb shrugs because of the large amount of weight that can be handled. It all depends bro. Maybe try both and decide what you prefer.