Pros
You will work with some of the most talented and intelligent people you will every meet. It is a very exciting work environment for sports fans and you will be proud to contribute to a true industry leader. It is a casual work environment, and in most cases everyone is very accepting of coming in late, leaving early or taking time in the middle of the day to run errands or to take care of family issues. Company gym is very nice and open day and night. You'll have some of the best coworkers you'll ever know.
Cons
Long, long hours. Always. Workload is always an issue and work/life balance is just a theoretical concept. Morale is very low (for anyone who's been there longer than 4 months) and management offers nothing but empty promises in this regard. Congress has a better track record of keeping promises, actually. Bristol is not an appealing place to live: There is nothing for young people to do, but Connecticut's high tax and crime rate make it equally unattractive for families. There are some nice areas and wonderful schools in the area, but your spouse would need a significant income if you wanted to live in any of those places. You may think otherwise, but it is actually harder to be a sports fan when working at ESPN. Instead of watching football with your family, chances are you'll be at work instead. Think about that for a minute. Promotions are inconsistent; standards vary greatly between departments. Compensation is significantly below market at all levels. Because so many people want to work for ESPN (or think they do) management makes no effort at employee retention; employees are generally regarded as expendable. Much of the technology used at ESPN is proprietary, so you techies will gain skills that are not often transferable. Did I mention the never ending long hours?