doubtful advantage

Janey had the doubtful advantage over other women that men (by men I mean Roger) always knew where to find her.

Respecting which we have to note first, that all such property is of doubtful advantage even to its possessor.

It would be of doubtful advantage to pursue the inquiry at length.

It also, and this was perhaps a more doubtful advantage, taught him to consider drawing as a skill in beautifying.

I understood,” exclaimed de Spain, following his doubtful advantage, “you lived out this way.