Apollo.io is a robust sales intelligence platform ideal for marketers and sales teams. Key features include a database of over 275M contacts, advanced filtering, email automation, and AI-driven engagement insights. It integrates seamlessly with CRMs and offers pricing from a free plan to $119/user/month. Compared to tools like ZoomInfo or Lusha, Apollo offers cost-effective, detailed options but can lack phone number accuracy and proactive customer support. Customer support speed and the learning curve for new users could be improved. Overall, it excels in data depth and functionality at a competitive price.