Pros
1. Get to deal with more complex issues than L2 engineers. 2. More closer to R&D then L2 engineers. 3. Deeper debugging and troubleshooting knowledge (as expected). 4. Get to share your knowledge with others (via brown bags). 5. Higher chances for internal promotions or career switches. 6. Expected to write more internal tools and fix supportabilities. 7. The 'Specialized' status (and expectations) when you join a call.
Cons
1. High workload. 2. Higher customer expectations (if anyone should know its PS). 3. Moderate learning platforms, more on self learning and exploring. 4. Harder to find a company with similar salary (as its high in INFA) and same access to code and freedom to build your own tools and share with team. 5. Most of us are geeks, so less fun.