Avantages
You will be given as much responsibility as you show you can handle, quickly, and will have lots of opportunity to learn new skills. If you have deep specialization in areas that are important to the business you will (probably) have pretty good job security - as long as the company stays in that business area.
Inconvénients
Entitlement mentality towards uncompensated labor from middle and upper management. Highly political and sometimes bullying environment, entrenched mediocrity in middle management, "blame the troops" backstabbing from incompetents. Managers and employees who understand and accept the status quo of "needing" to be highly political take credit for the work of others who won't or haven't figured out how to play the political game. Unspoken but well known mafia system where those who get made survive all layoffs regardless of whether they maintain their business or technical edge, and get to wet their beaks at the bonus pool whether they put in a strong contribution for the year or not. Company and upper management shift the product strategy and cede markets to nimbler competitors with regularity. Poor documentation & dissemination of company specific technical knowledge means that such knowledge resides only with those who are willing to throw work/life balance in the trash and do organizationally inefficient individual from-scratch learning (basically reverse engineering the company's own IP), creating a perverse differentiator for compensation and advancement , a two-class technical staff, and key personnel risks for the company. If you are a talented and creative individual, you are selling yourself incredibly short by becoming a lifer here.