(a) The lien provided for in this subchapter shall take precedence over, or be superior to, any mortgage or other obligation attaching against the property in all cases in which the holder of the mortgage or other obligation shall permit the property to remain in the possession and be used by the person owing and bound for the amount thereof.
(b) The lien shall not take precedence over a bona fide purchaser for value of any such property without either actual or constructive notice.