The right of compensation granted by this article shall have the same preference (without limit of amount) against the assets of an employer, liable for such compensation, as is now or may hereafter be allowed by law for a claim for unpaid wages for labor: Provided, however, That no claim for compensation shall have priority over any judgment, mortgage, or conveyance of land recorded prior to the filing of the petition, award, or agreement as to compensation in the office of the prothonotary of the county in which the land is situated. Claims for payments due under this article of this act and compensation payments made by virtue thereof shall not be assignable, and (except as provided in section three hundred and nineteen of article three¹ and section five hundred and one of article five hereof)² shall be exempt from all claims of creditors, and from levy, execution, or attachment, which exemption may not be waived.