Pros
My experience is limited to the Fraud Investigation & Dispute Services group within Ernst & Young. It is a diverse place to work, there are standard yearly terms for promotion, and compensation is comparable to other Big 4 firms. Your coworkers will probably be the most competent and helpful people you met, some of mine have become very good friends. Teams work well together, are generally cognizant of your personal life and allow for a work/life balance. Diversity is well accepted at the workplace and there are equal opportunities for growth and advancement within the firm. In addition, there are opportunities to travel globally on engagements (hectic hours though) and a lbal exchange program that allows you to do a 1-2 year assignment abroad after 3 years of experience with the firm.
Kontras
E&Y is a great place to get your career started and get your CPA license. However, you migh get stuck doing routine work. People with experience in certain types of projects are typically picked to work on similar engagements while those without experience often struggle to find meaningful assignments. This is mainly because the experienced folk will take less time (cost the engagement less money) to get the work done because there is no learning curve. Often, in larger offices, the staff is bounced around from project to project and do menial tasks like make binders or review emails. The experience is a bit different in smaller offices where even junior level staff get the opportunity to step up and perform senior level work. In addition, although everyone has assigned counselors, you might not have regular communications with your counselor. As a result, the counselor will often be out of touch with your career needs and opportunities needed to develop your career.