Pros
The company, starting with the CEO, treats employees as its core stakeholders. This belief flows down into everything the company does: the work-life balance, the benefits and facilities, the annual meetings, anniversary celebrations, etc. They've succeeded in making the company feel smaller than it actually is. Good products and a very stable profit model. The company has continued growing through the recent recessions. The company actually practices its Core Values on a daily basis and hires people who exemplify them. As a result, you end up working with people who are not only brilliant, but also great to be around. If you love engineering and science, you'll get to work on great technology and feel like you're making a difference.
Cons
Base salaries are relatively low for the software industry (profit sharing and work-life balance make up for this in my opinion). The company does not adjust compensation for location within the U.S., which is a pretty good deal if you're in the Novi (Michigan) office - not so much if you're in the Bay Area. (The observations below would be considered "cons" by some) The company is relatively slow to move in the marketplace, taking "measure twice and cut once" to the extreme. They will intentionally make conservative choices to limit growth. Promotions are entirely based on seniority, so don't expect to move quickly up the ranks. Note that annual raises are pretty good for high performers even if your job title doesn't change.