Pros
I've found the few months here at LinkedIn a great experience, the culture is very positive, open and collaborative, they value your own ability to succeed and be productive in your career and the perks are great. I find the transparency to be a big plus, coming from my experience in the industry it's not the easiest to find. The people here are generally very smart and great at what they do so it's usually very easy to find someone to help if you have a question.
Cons
I would say the biggest downsides are typically associated with any large internet company going through rapid growth - new products and versions are constantly being iterated through so things are in a state of flux. Work/life balance can be difficult depending upon how well you manage things.