Pros
Very "family" feeling (surprising for a mid-to-large company). There is a drive for results- but the environment is laid back. Competitive wages and benefits. Although all companies have their share of politics and red tape, Essilor has less than most. If you have the drive to succeed, you will be successful at Essilor! Finally, Essilor is the clear leader in it's industry- and the most stable. It has a very long track record of growth and is positioned for continued growth built upon the concept of employee ownership (Valoptec is the employee stockholders organization, and is the largest owner of Essilor stock).
Cons
The ophthalmic industry is interesting, but also unique. Essilor is still primarily a BtoB company (although it is steadily moving towards the consumer). Much of the communication is directed towards eye care practitioners and ophthalmic laboratories. The good news is if you can learn the quirks of the industry, you can go far within it. The bad news is, this is not cookie cutter marketing- just because you were able to successfully market shampoo doesn't mean you'll be successful with lens products and services.