> The only
>possible issue is that dumb bells can be uncomfortable on the
>shoulders when doing squats and other lower body work if you
>use heavy weights (for me, 15# and above are too uncomfortable
>on my shoulders).
I have a hard time putting any dumbells on my shoudlers: I never understood how Firm instructors did it without it hurting. Instead of placing them ON my shoulders, I hold them in front, like in a hammer curl that is taken a bit farther. I can prop them against the front of my shoulder a bit there (where there isn't as much bone as on top of my shoulder area) and it feels okay.
Another option is to hold the dumbells down at your side or, for plié squats, on the point where the thigh inserts into the hip.
Dumbells actually have advantages over barbells for upper body work especially, including working each side equally and not letting the strong side take over from the weak, and engaging more stabilizing muscles, making the exercise more functional.