Pros
Fairly relaxed environment except fabs. Flexible about work-life balance, which has become a buzzword at many companies (it wasn't always that way). Management overall tends to be fairly respectful and humane with employees, though there are exceptions. World-class scientists and engineers mean you can really learn a lot here. Nice 'college campus' facility; pleasant, wooded surroundings with relaxing, calming environment even including wildlife (foxes, even).
Cons
Very little room for advancement - many technicians and engineers stay at the same level for 20-40 years, with just minimal raises (often 1-2%; none this year due to economy). Favoritism can be a problem depending on the specifics of the people and management in a group. Layoffs are the norm here - don't expect to move here and be here for five or ten years - you will have no idea if you'll be here six months or you might end up being able to stay 40 years - but the people who outlasted many layoffs to stay that long are really the exception.