I would avoid this for now. Just my opinion. Not endorsed by me. ; - )

There is no penalty for using the service (right now). But, that does not mean the service provides off page ranking factor. And,even if it currently does provide ranking factory, it does not ensure that the big G is working to filter out the benefit. There is no question that the effectiveness of paid link is going to be rubbed out.

Remember, there was a time where people did not believe that the effectiveness of T.E. would ever be significant diminish