Pros
Good for learning the ropes in commercial law practice (for a young lawyer starting out). Diverse areas of practices and high-profile clientele. You learn not only the practice but also corporate culture/management. A good number of smart and helpful colleagues. Doesn't look bad on your CV if you plan to move on. Average salary but still above industry average (most other law firms pay very badly). Health insurance and pension contribution are covered.
Cons
Terrible management and company culture. Bullying and harassment is common. Little independence over work. Extreme workload with no overtime pay or consideration. You will not have a life. Hardly any room for career progression. Unimpressive salary (other top law firms pay better). Insecure job as employees are frequently fired without notice. Little training of employees. Inflexible work, remote work option not available. Some favoritism, too.