I haven't had a back or neck ache since I went exclusively to old style comfort 70d swept bars, except when I had them too low. About 29,000 miles since 2012. I have my left hand on the grip and the other on the bend a lot. NOT possible with drops. Temporary hand aches are unavoidable.
Yesterday I rode my 1973 CCM with new SA RD3 / 650B wheels.... 100.6 miles, 8 hrs moving. This bike likes to go 14 mph LOL. Doesn't seem to matter what way the wind is blowing.