ProProfs Chat in my opinion without a hint of doubt.
Lead generation pages are the most important for any business and watching users slip through the cracks and leaving without a purchase is quite disappointing.
With ProProfs Chat, our chat operators get notified whenever a visitors arrive at our sales page so that we can buckle up in advance. It also shows what all options a visitors are browsing and how much time each user is spending on a page. And then, we simply nail it with a proactive invitation, asking users about the queries they might be having.
The best part, it seamlessly integrates with Salesforce and information about any visitor initiating a chat gets directly posted on the Salesforce dashboard.