Pros
ESRI's greatest asset is its people. You'll routinely find talented people who are and proud of their work. Personally I work in the sales division. Whereas some organizations are "quota, quota, quota", the ESRI sales philosophy is 100% customer-centric. It would be unacceptable to sell a customer product or services they don't really need, even if it means a smaller PO. It's this ethical approach that allows us to implement larger scale solutions with larger invoices. Regardless of revenue, the approach is always the same. Learn the our customers' real problems, and recommend the best solution.
Cons
The easy answer might be the salary. Having the same responsibilities at a different company would probably provide a bigger paycheck. On the other side of the coin (pun intended!), ESRIs financial health resulted in ZERO layoffs during the current financial crunch. I'm ok with making a little less, but knowing my job is secure!