[morzh]

60 Watts at 115V makes for roughly 0.5A. 10V dropout will dissipate 5V max, which will require a 10-15W resistor. It will not get overly hot but 5W is still a bit of dissipation.
It is safe both ways, the transformer probably a bit more expensive but is a cleaner way.

Also the dropout with resistor at least in theory will vary with power, so at low volume it is less. By how much I do not know. Maybe not by much as 3 to 5 watts is not a lot compared with 50 to 60 watts overall.