The site is so big and there are so many different groups & businesses it's hard to say exactly what the atmosphere & working requirements will be. I believe alot of the negative press is in relation to the call centres where like all places, their probably underpaid for the work & crap they have to take. If your in the professional technical roles, things are a lot different.
I know a lot of the engineering technical staff have a really good work life balance. They're on flexi time so come and go as needed (obviously within reason). Management are very lenient to working from home the odd time if something comes up. As long as the work is getting done well, there isn't an issue. As you rise the ranks and depending on the programs you are working on, there can be some late evening teleconferences (late: 4-6 west coast US, or early 7-8 Asia).
Overall I think it's a great place to work once you get settled. People are really friendly and there are always big site events throughout the year. If you have kids, they do a lot of things for the family aswell. There's a kids Christmas party every year, a fun day during the summer etc
What business are you applying too? (IPG, ESSN ?) So in relation to work life balance, I'd say it's one area they're really good at. Feel free to PM me if you'd like more specific info. Good Luck.