DS 1 and his then fiancée planned to do this at one time, for the same reason. That plan changed to each keeping their own surname. DS 2 and his wife went on to do exactly the same thing. However, one dil has since started using our surname instead and the other talks about doing that too, largely, I think, because it is simpler for them to have have exactly the same surname as their children.
Initially, we felt slightly 'upset' that our dils and future dgc might not have our surname, but over time I have realized that it really doesn't matter one jot. In fact, if I had my time again, I am fairly sure that I would keep my own original surname!