Totally agree with Josh. Best bets are driven off of the Lead Score: Leads with the highest Leads score that have been most active in the past week will show up on top. I believe top 5% of lead scores gives 3 stars and top 5% of increase in lead score gives 3 flames. If you find out from the team why certain leads aren't good, adjust the scoring to give them fewer points (or give negative points for undesirable behavior).
Hope that helps.