1. Deployment Method: IBM QRadar is typically deployed on-premises, requiring dedicated hardware and software setup, which can be more suitable for organizations looking for complete control over their security environment. In contrast, Zscaler is a cloud-based security platform, enabling quick deployment and scalability, making it ideal for organizations with distributed or remote workforce.

2. Focus on SIEM vs Secure Web Gateway: IBM QRadar is primarily focused on Security Information and Event Management (SIEM), offering capabilities for log management, threat detection, and incident response. On the other hand, Zscaler specializes in Secure Web Gateway (SWG) services, providing cloud-based web security, URL filtering, and data loss prevention.

3. Integration with other Security Tools: IBM QRadar has extensive integration abilities with various security tools and technologies, allowing for comprehensive threat intelligence and incident response capabilities. In comparison, Zscaler integrates well with cloud-based services and applications, offering seamless security without the need for additional hardware or software.

4. Threat Intelligence Feed: IBM QRadar provides access to IBM X-Force Threat Intelligence feed, which offers real-time updates on the latest threats and vulnerabilities. In contrast, Zscaler leverages its cloud infrastructure to provide threat intelligence based on web traffic patterns and behaviors, enhancing security effectiveness for web-based threats.

5. Cost Structure: IBM QRadar typically involves upfront costs for hardware and software licenses, along with maintenance and support fees. On the other hand, Zscaler operates on a subscription-based pricing model, with costs depending on usage and the number of users, providing more flexibility for organizations with fluctuating security needs.

6. Scalability and Performance: IBM QRadar may require additional resources and configuration for scalability and performance, especially in large enterprise environments with high volumes of data. In contrast, Zscaler's cloud-native architecture allows for automatic scaling based on demand, ensuring consistent performance and reliability.

In Summary, the key differences between IBM QRadar and Zscaler lie in their deployment methods, focus areas, integration capabilities, threat intelligence feeds, cost structures, and scalability/performance approaches.