Pros
It is a good place to grow and learn new things. A lot of knowledge sharing goes on. Most of the employees are pretty smart. Also benefits are pretty good (free food). If you are starting your career this may be a good place to start out and then move on later.
Cons
I've heard Wall Street on Demand called a "Churn and Burn" company, and it is absolutely correct. They work you ragged at all hours of the day and expect quality work. The pay is pretty bad compared to the amount of time you are overworked. Many people have complained to upper management about this and they say they reward those who are good employees. I didn't see that happen very often. HR is well aware that they have problems firing people when they need to be fired (admitted in a meeting to the whole company). It reflects pretty poorly on the company that they don't seem to know how to manage their own employees. Toward the end of my time working there, the issue of resource management on the computers was becoming a huge problem. There were days I couldn't get work done because it took hours just to obtain what I needed to do work. Documentation is lacking for some clients because employees have no time to document the work, they only have time to fix problems and work on new projects.