Originally Posted by Bagi Zoltán

Domain authority suppose to be more important nowadays which can be improved by relevant backlinks from different domains. If i were you i would try to diversify the links as much as it is possible. The diversified anchor texts, seem to be more natural, and always help me to strengthen the rankings so far.

Answering your second question is more difficoult for me. Many of the link bid scripts are the creation of the last few months, and it's absolutly not sure that they PR will be exported during the forthcoming update to the toolbars. I have no experience how google handles those sites in the light of relevancy. If you want to buy link for PageRank i suggest you to visit backlinkwatch.com or Yahoo! Site Explorer in order to esteem the potential PR flow.