There is no battlecard yet created for sangfor and meraki. you can instead check for their data sheets

Meraki vs NGAF# both have cons and prons .It depends on the customer requirement and both are using for network secuirty solutions .

Meraki vs NGAF# both have advantages and disadvantages .It depends on the customer requirement like budget ,infrastructure  .what security measures customer required

Criteria	Sangfor NGAF	Cisco Meraki
Network Security	NGAF offers advanced security features such as Anti-DDoS, WAF, and Sandboxing.	Meraki offers standard security features such as firewall and VPN.
Management	NGAF has a user-friendly web-based management platform, with customizable dashboards and reporting.	Meraki has a cloud-based management platform with centralized control and automated policy enforcement.
Scalability	NGAF can scale up to meet the demands of large enterprises, with up to 100Gbps throughput.	Meraki is best suited for small to medium-sized businesses, with limited scalability options.
Performance	NGAF delivers high performance with low latency, utilizing advanced hardware acceleration technologies.	Meraki performance can be impacted by the number of users and the amount of traffic.
Price	NGAF delivers high performance with low latency, utilizing advanced hardware acceleration technologies.	Meraki performance can be impacted by the number of users and the amount of traffic.
Integration	NGAF can integrate with a variety of third-party security and management tools, such as SIEM and Syslog.	Meraki has limited integration options, and is primarily designed to work with other Cisco products.
Support and Services	NGAF provides 24/7 technical support, with a dedicated account manager and access to a comprehensive knowledge base.	Meraki provides support through online resources and a community forum, with paid support options available.

Cisco Meraki is the leader in cloud controlled Wi-Fi, routing, and security. Secure and scalable, learn how Cisco Meraki enterprise networks simply work.
"Sangfor NGAF specializes in ransomware detection and helps to protect our network from ransomware threats and malware."
"The firewall system needs gradual improvements because there are more threats and challenges every day."

You cannot compare Cisco Meraki to Sangfor since they are not similar product kind

You cannot compare Firewall (Cisco Meraki) to Next Generation Firewall (Sangfor). The winner is NGFW