Pros
Awesome place to gain experience as a student.
Good software engineering workflow, I gained a lot of experience with Git, Linux skills, Agile workflow, Chef and other technologies & tools.
Working at the Open Source Lab gave me a lot of useful experience that allowed me to hit the ground running in industry when I graduated. It is VERY valuable experience if you want to work in DevOps.
Additionally, it was a fulfilling experience to support a myriad of awesome, open source projects. What the Open Source Lab does is a very important part of the software dev field and now in industry, I often see our builds pulling from OSL mirrors.
Additionally, OSL is very flexible with student schedules, they were very flexible with hours and allowing us to take time off for finals/midterms etc...
The onboarding process and documentation is very good, as OSL has a regular inflow-> outflow of incoming and graduating student devs.
Cons
Can be a little bit isolating, I was usually working alone, remotely and didn't get a ton of opportunities to collaborate with other student developers on projects.