We came across a backlink exchange offer from directory site with millions of visitors per month, however, when we use MOZ plugin to check its domain info, it has an alarming spam score. We used to solely reply on Google Pagerank to determine if it is a website we'd like to receive backlink from. Our questions:
1. a high ranking domain with spam score but millions of visitors, should we exchange backlink?
2. what are most important metrics to judge a backlink and domain value in 2017?
3. please recommend us some tools that you use to see these metrics.