Originally posted by gopro
-the fact that with dumbells you can slightly alter hand/wrist position, and/or plane of movement to make an exercise more comfortable and effective
This is a big factor for me with DBs. I can find the right "groove" easier and make adjustments in a way that's easier then bb or machines for most exercises.
I like to mix it up between BB DB and machine but this is a big reason I personally like DBs best for most upper body exercises.