* You are outside the company hierarchy - That means you actually have 0 power normally. Most consultants / contractors I've worked with have to do exactly what they are hired for no more or less. Permies generally have a bit of wiggle room and you should get more the further up the pole you go
* You have to keep learning - That's right slow down for even a year and you can be left behind in consulting. At least as a permie I can catch up at my own pace
* You get more exposure - For the types of companies that hire consultants this is a downside. The exposure you be getting is to toxic workplaces. They even admit this in the JD "the customers we work with will use legacy practices and technologies. "
* You meet lots of people - I already have plenty people in my life this isn't a positive for most programmers it's a negative.
You know who's the first to be fired when times are a bit more rough...