I own both, along with .308, 25-06, 7mm Mag, 300 Mag, as well as several others. But my gun of choice for white tail deer is still the .243. I hunt fairly open country so I don't have to worry about plowing through thick cover, and most of my shots are less than 100 yards, I shoot a mild load in the .243, but it doesn't destroy meat, and has never failed to provide me with table fair.
Most whitetail hunters are either over gunned, or under gunned, I think the .243 is a happy medium.