Pros
LinkedIn has an amazing laid back company culture (I work in the NYC office). There is always fun things going on at the company to take part in. Sales compensation is good: hard work is rewarded. The company is managed really well, the organization is responsive to the needs of employees, and there is tons of free food. The 401k plan is great (50% match up to IRS max). Process and systems are changing and this is because the company continues to grow. There is lots opportunity at LinkedIn to improve yourself professionally and the company is very supportive of your needs.
Cons
One suggestion is they could award stock options (or restricted shares) at year end to top performing sales people as a retention tool. Overall, in my 10+ year career this is the best company I have worked for so far.