The ability to integrate with a variety of platforms and the ability to add multiple fields to a lead. Some of the lead conversion options can be confusing. The reporting can also be a bit cumbersome. If you are looking for a lead management system that will help you automate your marketing process I would look into Popileads. I am able to quickly add new leads to my database and then use the reporting to determine which way to market my leads. This allows me to streamline my marketing process and helps me see results faster.