They may tell you up front that you should not be working longer than a 40 hour work week, but that is just something they are required to tell you. Most of my team members would leave work to go back home and then continue working from home. Whatever they want done will get done, whether it harms your mental/physical health or not. Challenging is not the word here, work horse is a better word.
I found the leadership to be subpar. I've worked with great leaders in the past and the AWS leaders to not have well developed people skills. Every job has challenging and tough tasks, what makes these tasks easy or difficult is how the leaders above you motivate you through the tasks. I found the leaders to have very little empathy and high egos.
There is a actually a cultural difference as well. There are many foreigners that work at AWS who's native culture is all about working. They take pride in working 60-80 works. I'm not against hard work, as it builds character, but their is a limit. You shouldn't live to just work. You should work hard but enjoy life. Work-life balance was almost non-existent. If you don't come from one of these cultures, good luck.