If you have only one TV, and it can 'add-scan' or it permits manual direct entry tuning of real channel numbers, then a rotator may be of use to you.
If you have more than one TV, a rotator is going to be hated by the viewer who does not get to control it.
Another problem arises if you have a TV that only tunes stations found by scanning. This problem is worse if the TV forgets all previous scans each time a new scan is run. A full rescan each time you turn the antenna is an agonizingly slow process.
I would opt for a main antenna system using fixed aim. If you want a DX antenna that you can look for off angle and distant out of market signals with, add a second antenna system that cables separately to a set top box tuner, preferably one that can be manually configured or at least accepts 'add-scan' entry of new channels.
http://forum.tvfool.com/showthread.php?t=820
http://forum.tvfool.com/showthread.php?t=2882
http://forum.tvfool.com/showthread.php?t=8275