As of my last knowledge update in December 2023, several top applicant tracking systems were prominent in the market, each with unique features. Notable among them were:

  1. Workday Recruiting: Renowned for its user-friendly interface and integration with other HR modules, Workday offers a comprehensive solution with analytics and mobile accessibility.

  2. Greenhouse: Known for its robust reporting and analytics tools, Greenhouse focuses on optimizing the hiring process through data-driven insights and customizable workflows.

  3. ICIMS: ICIMS stands out for its scalability, catering to both small businesses and large enterprises. It emphasizes a streamlined candidate experience and integrates with various HR systems.

  4. BambooHR: Particularly suitable for small to medium-sized businesses, BambooHR offers an intuitive ATS with features like employee self onboarding and customizable workflows.

  5. Jobvite: Jobvite is recognized for its social recruiting capabilities, leveraging social media platforms for talent acquisition. It also provides an integrated platform for recruitment marketing.

While these ATS systems share core functionalities like resume parsing and collaboration tools, their unique features, scalability, and focus areas differentiate them. The choice often depends on the specific needs and scale of the organization, as well as preferences for user interface and additional features. Keep in mind that the landscape may have evolved since my last update, so it's advisable to check for the latest information and reviews.