Pros
SAP is full of really bright and ambitious people. It sets ambitious targets for itself and it's people. If you can survive in SAP, you can probably work in any company in IT. It is so large that it's very unlikely to be taken over, which makes it a stable environment in that sense. Perks vary from ok to excellent, depending on which country you are based. Company culture is moving from it's original German to a more American type of culture.
Cons
Tends to manage everyone and everything by metrics. Employee satisfaction ratings have been falling in recent years - the company is clearly trying to do something about that at the top level, with a lot of talk about work/life balance. However, this doesn't always transfer into reality in the field, where constant revenue pressures make that difficult to achieve. Career opportunities definitely exist, but job vacancies aren't always advertised internally' there doesn't seem to be 100% transparency to allow people to apply for internal promotions when available.