Pros
The people who actually do the work there (ie the scientists, technicians and lab aides) are hard working (they have to be otherwise they get fired!), dedicated and talented (those who haven't been laid off in the most recent round of "payroll adjustment" that is). You get to work on a wide variety of different chemistry projects, and you'll certainly never be bored.
Cons
Where to start? I regularly worked 55-60 hour weeks, 7am to at least 5pm (frequently later) during the week, often coming in at weekends (I would estimate I worked about 30% of my weekends). On at least three occasions I had to work 24 hours straight. Eventually I was burned out. When business tanked during 2009 I was let go, and in an extremely unpleasant manner. Compensation was not, in my opinion, commensurate with the effort I put into the job. The management philosophy of the place was definitely much more stick than carrot. The caliber of most of the management there was nothing short of abysmal.