Pros
Rackspace truly does care about it's people. This company hangs its success on delivering world class service to it's customers, and management understands that keeping the employees engaged is vital to that process. They do an assessment of every employee's strengths and they work hard in getting people matched with jobs that match those strengths.
There is a high level of autonomy with respect to getting the job done, and employees have a lot of freedom in dealing with customers both internally and externally. It is a fun place to work with very relaxed atmosphere. The culture is extremely important to everyone, and there are plenty of cool events, celebrations, Nerf dart wars, and team outings to keep things fresh.
Change happens a lot at Rackspace. It is an extremely nimble company in a red hot industry, so anyone seeking work at RAX should be ready to move fast and change seats often. But that fast pace also makes it a very exciting time to be a Racker - The growth is incredible, which means a wealth of opportunity and upward mobility not to mention the pride that comes from being a part of such an awesome company. Love it here.
Cons
Fast growth makes for difficult communications sometimes. Employees must be proactive participants in information exchange.