Pros
Company culture - a sense of everyone pulling together and the stated goal to try keep the cohesiveness of a small company despite rapid growth. The CEO is a top class leader in his ability both to inspire and to deliver. The company makes strong and very visible efforts to provide a positive working environment and to be "last job you'll ever have", and focuses benefits where they matter such as a generous professional development allocation. Consultative about what employee benefits should look like, leadership is highly approachable. For software developers there is a sense of being valued as the foundation of the company's product. An excellent share options scheme adds to the enthusiasm people feel for the company's success. The past success and future prospects for the company are the stuff of fairy tales, and the sense is of a once in a lifetime opportunity to be involved in something huge.
Cons
Rapid migration from a small regional company to a large multinational and significant market challenges means constant change, no complacency and no absolute certainty about what happens next. Its not clear whether culture can stay as it is or whether large corporate syndrome will start to take effect. Its not a place to hide but to engage your own entrepreneurial aptitudes!