Pros
The main reason to work for KPMG is the career advancement opportunities available after you've worked at the firm for at least 2 years. I've found that having the 2+ years experience on your resume almost guarantees you will be hired into a higher salaried position than if you don't have it. It is faster to work yourself up at the firm than work your way up in industry. If you stay focused on that, it is worth putting in your time with the firm.
Cons
The biggest downside is the demanding pressures of constantly trying to balance work and life. This is especially difficult if you are married and/or have kids. Although the firm preaches work/life "balance", this really is not the case. You can only focus 100% on one or the other. You can only be an EP at work or home--you choose. Usually, you justify working those insane long hours and missing school events by believing that all this sacrafice is for your family's future. In reality, there is no work/life balance at KPMG.
