Very different from the early start up or even mid sized company days (understandably). Corporate, crowded- there is constant pressure and competition to stand out from the crowd. All employees are intelligent and motivated and striving to impress so it's easy to become a 'mediocre performer' if you aren't constantly upping your game. Can be challenging if you have significant responsibilities outside work but is the best place to work if you are young, energetic and relatively 'free' to dedicate most of your life to it.