Pros
SAP has competitive compensation, practically guaranteed large bonuses, benefits and even decent stock option and employ stock purchase programs for such a large company. Palo Alto campus is in a nice location and in general colleagues are easy to work with and have a good attitude towards achieving success, solving problems, etc. SAP typically has long retention, minimal attrition and very few layoffs (almost unheard of), which I believe speaks to the general happiness and satisfaction of the employees. Many colleagues have deep expertise and knowledge and in general are willing to share and help w/out the attitude that many very senior employees typically have at other tech companies.
Cons
Much of SAP technology is antiquated and if you are an engineer there's a good chance you'll be working with their business suite (their largest and most important/lucrative product) which is complex, outdated and implemented in a proprietary programming language called ABAP. In Palo Alto there is a fair amount of modern development including cloud, mobile, HTML5, etc. However to varying degrees you can never get away from the R3 ABAP stack. Efforts to modernize the SAP product line is sometimes misguided or does not make sense with today's trends, but nevertheless the effort is there and in general is bringing SAP into the modern software world, albeit on a somewhat bumpy road.