Pros
I joined the firm as someone with 2 years experience in Big 4 accounting. Although I have only been here a few weeks, I have been exposed to/learned A LOT. Although it is a medium size, you will get Big 4 training in a much more intimate environment. I have received the opportunity to learn about the ins and outs of corporate/business taxation and how it affects the individuals full circle. YOU WILL NOT get this many other places in my opinion!
Cons
So far the only downside, in my opinion, is that the firm is really big about having staff arrive promptly at 8:30 (within reason especially after busy season late nights). I can understand this policy and it probably works for most, just not me as I live a bit farther and am not an early riser. Pretty much the only negative I can think of thus far