Pros
There is always interesting work that involves some exciting science. There are plenty of opportunities for new challenges, opportunities for advancement/promotion, plenty of training and the opportunity to work with international teams. Some of the infrastructure and tools we have are great. The compensation is good compared to other European countries. The Basel Campus is beautiful with some very pretty architecture.
Cons
The culture heavily depends on the management in charge of a department and that can change overnight during some of the frequent reorganizations (1 to 2 times a year). It's a large company with some bureaucracy, politics and the occasional one-size-fits-all-policy. Sometimes the workload can go a bit out of control e.g. when there have been mass lay-offs or when extra projects come up. When that happens, the company can be very slow to respond (especially if there are severe budget restrictions in place due to e.g. some major patent expiring) and it may take months until things stabilize again. Nearly all offices are open space offices with, say, 50 people on a floor. These are usually a bit like call-centers with a lot of noise, because about half of the available private rooms will typically be reserved as de-facto offices for those that feel that have enough power to intimidate others into not using the rooms.