No impact at all to sound. But it is easier to control than some of other solders (mostly due to the smaller diameter).
Note, if you get the lead free, it has a higher melt point, so you need to watch your technique and if needed, use heatsinks to make sure you don't toast anything important. If you are new to soldering, get the leaded variety.
Edited by liamstrain - 7/4/14 at 12:02pm