Pros
Laid back environment. The technical people here are some of the smartest and most competent people I know and generally friendly. I do believe in the CEO and his vision for the future of Rackspace. This company has almost had no layoffs during these bad economic times. Good Benefits. Ability to learn a lot from your peers.
Cons
After hour shifts do offer a 10% to 15% differential, but you will not be able to be a part of many of the cultural aspects of Rackspace. Intensive after hours is overworked and understaffed due to a narrow profit margin and middle management who doesn't see System Administrators as anything valuable (due to ignorance and being obsessed with metrics). You will be slammed into a high volume ticket queue with management promising that it will get better, but it never does. The pay increase between levels is a joke. The only serious pay increase is when you are willing to take on a position that puts you on call 24/7. All pay levels are still under market rate.