Ah, that I could remove Wards at my whim. I trust that Polare has answered your question to your satisfaction, I cannot think of anything of consequence to the average traveler to add. I reccomend Wards for just that reason, well, that and not only is it difficult for me, as the caster, to drop a Ward, but it is equally difficult for anyone to do so. However not everyone has the means to pay for a Ward, or the contacts, in some cases, and so Wizard's Locks are quite literally 'the poor man's Ward.' Which I am more then capable of dropping 'at my whim' should I choose to do so, but so is anyone else.
As Polare said, the key is that no one can tell the difference between the two without trying to destroy it. And of course, although I didn't say so, I wouldn't tell anyone whether you had purchased a Ward or a Wizard's Lock, as discression is part of what you get in the deal. Besides, who would buy building defenses from a disreputable source?
~Kerjal