Pros
The most positive thing about Zurich is that it is so diverse that if you're ready to move to a different role you should be able to do so fairly quickly. At Corporate Center you can find a variety of roles in an english speaking environment, while with Zurich Switzerland you have the (swiss-)german environment. The flexible working hours are also a plus. A few years back I would have also mentioned the benefits such as reduced insurance premiums - but even with the discount you still end up paying more than with competitors. Paid time off though seems fairly generous for vacations or other leaves. The discounts for public transport are also nice, although pretty standard in Switzerland.
Cons
First, as in most companies, your experience will depend a lot on your manager. I've been in a variety of roles since joining Zurich with ever changing managers - most of them had no people management skills, two were great and luckily one of the two still is my manager. Apart from hiring people managers with a significant lack of people skills, you should not expect too much support with regards to anything relating to personnel costs. You can attend a lot of internal courses but getting an external accreditation will only work if you're friends with the right people. Same goes for salary increases, performance ratings and promotions. Either be patient, make friends with the right people or leave. Overall making progress (in whatever area) takes ages at Zurich. Everyone gets a say, while no one wants to decide. So everything drags on endlessly or goes in circles, round and around.