Too much focus on the value of the Impact Factor itself is probably not useful but I believe that the Science Citation Index (SCI) and the quartile rankings (Q1 - Q4) are important. As a group, my experience is that the review procedures are better in the high level groups as Q1-Q2 since the number of submissions are higher. The quality is therefor generally better.
A discussion of how this information is used in research proposal evaluations and researcher classification is given in the link below: