To publish or not to publish a paper in an ERA "type C" conference?

I have been researching a topic in Computer Science for several years now. The topic was interesting, but while I managed to get some conclusive results, I was not completely happy about them. It was like something was missing, but I knew that I really needed to talk to somebody more specialized in the topic, but unfortunately a lot of external professors that I contacted did not have enough time to collaborate. Anyway I submitted it to two conferences, which were ranked like B according to the Excellence in Research for Australia (ERA) schema:

A* - flagship conference
A - excellent conference, determined by a mix of indicators

B - good conference, determined by a mix of indicators
C - other ranked conference venues

The final verdict at both conferences was a weak reject. So I made the corrections that the reviewers suggested and submitted it to another conference. This new conference has a rank of C, but it deals with the subject that I was making research; the final verdict was accepted as a borderline paper.

Now, the question that I have is that if I should present my paper at that conference, or should I try to fix other things and resubmit to other higher-ranked venues? For me it would be more practical to leave it as is, and let another researcher pick it up if she is so interested.