I agree, rotators pose problems for households with two or more TV's connected to the same antenna.
The A/B switch solution has the benefit of being inexpensive, easy to install, easy to use and by being protected from the elements... long lasting. The only circumstance I can think of that would cause me to advise against the A/B switch solution is when you have a TV that does not provide for manual channel addition or automatic 'add-scan'. One of the TVs in our home is of such design. Every time one scans for new channels, the TV forgets all learned channels, then scans afresh.. it has no provision for manual tuning of real channels either.
If you face this situation, you may want to consider this idea:
http://forum.tvfool.com/showthread.php?t=2882