Pros
I was exposed to a high volume of transactions (something recruiters typically like to see). The company gave me increasingly harder and more complex deals to look at as I became more experienced. Their vacation policy was generous, I had the standard two week/yr previously and when I joined the investment bank it automatically became four weeks. You will never be able to take that much vacation with the workload, but it does help if you are laid off (which I was) or need to take a leave of absence since you must use your vacation first. The bank also likes to keep up with technology, probably stemming from the top--it's a priority for Jamie Dimon.
Cons
Its an investment bank so you will work long, long hours. There is hardly any administrative support. The organization is flat and unless you are politically savvy, then you will toil in your cubicle. Further, I worked in a regional office so it is very difficult to make much headway when no one from senior management sees you face to face everyday. I noticed that those who started at the same time, but worked in the NY main office did much better than those who worked elsewhere. There is a hyperfocus on containing costs and expenses, again, this being a priority of Jamie Dimon.