I am evaluating Rapid7's Nexpose VA and I have been getting some rather inconsistent results. No two scans have matched yet the environment I am testing in, our unclass lab, has not changed. Have any of you had similar problems? What were your solutions?

I am also open to alternatives. We currently use Nessus, but because their licensing is changing here at the end of the month, we are looking for a new tool. Thanks gang.