Pros
You get exposure to a lot. You will be working with other interns all the way up to partners. I worked closely with partners majority of the time I interned there. Also, you will get to see many different types of tax issues and even interact with clients. Everyone was very helpful.
Cons
They are still working to streamline the training process. It's difficult to cram all the info into such a short period of time in a way that actually teaches you something. Wasn't too effective. Learned much more throughout just by learning on the fly and asking questions. Long hours, obviously. Worked a few 80 hour weeks, which I hear is on the higher end. Also, they are more likely to extend a second internship if you're not graduating in the next semester. They do not offer full-tim positions if you're a year or more away from graduating which sucks.