Vantaggi
Upward mobility, opportunity to do many things in many different areas of tax, resources and name recognition of a large firm. Most people are very driven, and the opportunity to network within the firm is great. You have extensive client interaction, and really the opportunity to take all the work you can handle. As an attorney, EY is a great place to learn a lot about tax and gain great experience, which will undoubtedly improve marketability down the road.
Svantaggi
Note: this review is from the perspective of an attorney that joined the firm to hopefully do tax consulting work. First, compliance, and a ton of it. There is no way around it at EY. The diversified staff group system, where you are required to have x amount of hours in x amount of different tax areas, many times just means you will be doing federal compliance, then int'l compliance, then state and local compliance. Second, some of the people here have NO LIFE. They literally stay at the firm all night, their friends work here, if they can find a girlfriend, she probably works here too. In the event that you have to work for someone like this, your life is over until the engagement ends or you somehow get out of it. As an attorney, this can be tough, because many times the work will be mundane and tedious (printing, making pdf files, processing, etc.). During busy season, you will have no life. Third, the ARMS system. This is totally worthless, but you spend a lot of time dealing with it. Fourth, you really have to be aggressive and persistent to find the good work. If you can't find it, more compliance to stay chargeable. Fifth, the office is pretty stiff. Everyone is nice, and I like working with them, but there aren't many people I would like to get drunk with after work. This isn't a major concern, but its nice to have that when you need it.