Pros
It's good for a person right out of school because you learn a good deal about the consulting side of the tax business. It's nice for learning audit process, etc. that you will be able to take with you to a better opportunity.
Cons
It's incredibly political and if you're not in the Dallas office, you're a nobody. Egos dominate the culture, so much so that you're better off hiding than you are raising your hand to do more work. They make a big deal of their "flexible work place" but in truth, if you take a vacation you will come back to judgmental looks and backhanded comments. Advancement seems to come from beating someone else down far more than from merit or hard work. Ryan is also quite fond of lawsuits against clients and against other firms. When you go interview other places, they will be a bit wary of you with that on your resume. It's not the end of the world, because they will also assume you have good industry knowledge. However, just be cognizant of the possibility that someone at a different firm will have had a bad experience with Ryan. If you end up on a good team who makes the company alot of money and you get big bonus checks all the time, then it's great (presumably). But if you end up on the other kind of team, which is more likely, your time at Ryan is done before it begins, for all intents and purposes. Really, the most important day at your time with the company is the day they assign you to your team when they hire you. Something you have zero control over. You will be viewed almost instantly as a burden and they will push you out one way or another.