Pros
They hire physics and math majors from top-notch universities. You will find many smart and nice people there. Being a physicist, you will learn a lot about IT. Fast paced environment - a projects might last less than a year (for many - it might be a cons). Quarterly meetings are very entertaining - each employee might talk about anything which might be relevant for the firm for 5 minutes. They match 100% on 401K. You have to achieve 2000 hours a year goal. This will be below 45 hours a week, so despite others claim 50 hours, the average PCIer makes less than 45 hours a week which is not too much in my view compared to the other consulting companies.
Cons
If you are a physicist or a mathematician (and more than 50% are), you might feel that your skills are not used. But it really depends on your perspective, after all - if you are a physicist, why not to stay in academia.