1. Focus on Crowd: Bugcrowd relies on a large global crowd of ethical hackers to identify vulnerabilities in clients' systems, while Cobalt employs a smaller, handpicked group of security experts for their testing.
2. Pricing Model: Bugcrowd offers a subscription-based pricing model, allowing clients to pay a fixed fee for a certain number of tests, whereas Cobalt charges clients based on the severity of vulnerabilities discovered.
3. Reporting Structure: Bugcrowd provides detailed and comprehensive reports on vulnerabilities found during testing, including remediation advice, while Cobalt focuses on delivering concise reports with actionable insights for clients.
4. Testing Platform: Bugcrowd has a user-friendly platform with a variety of testing options such as bug bounties and managed services, while Cobalt provides a streamlined platform focused on penetration testing services.
5. Expertise Levels: Bugcrowd offers a wider range of expertise levels among its crowd of ethical hackers, from beginners to experts, while Cobalt's security experts are handpicked for their advanced skill sets in penetration testing.
6. Customer Support: Bugcrowd provides extensive customer support throughout the testing process, offering guidance and assistance to clients, while Cobalt offers dedicated customer success managers to oversee projects and ensure client satisfaction.

In Summary, Bugcrowd and Cobalt differ in their crowd focus, pricing models, reporting structures, testing platforms, expertise levels, and customer support approaches.