Which is better: giving charity to beggars whose circumstances are questionable, or to houses of Allah?

If the charity is voluntary, then the matter is easy, and its giver will be rewarded for his intention, even if it is spent in an improper place. However, if it is zakat, it must only be spent on its eight categories mentioned in the Holy Quran. It is not permissible to spend it on building or repairing mosques. The poor and the needy are to be believed in their claim of poverty and destitution, unless there is suspicion that contradicts them.