Pros
For the record, I was with AMLLP's San Jose branch for about a year. It was definitely a decent place to work. You're not working in Disneyland, but they do put effort into making it a hospitable environment, they host employee events here and there that are actually fun, release tension and give a work family environment. Aside from tax season crunch time, I didn't hear of people being turned down for vacation requests or reasonable time off. Management that I interacted with were decent people trying to get a job done while leaving as many people satisfied as reasonably possible. Also their 401k and internal financial planning services were a cut above average.
Cons
Despite the surface pleasantries, there's some under the surface misery from some of the staff. Accounting isn't for everyone, and there was a significant contingent of employees that were in it for the decent pay, but were slowly watching their happiness drain away as the job brought them 0 fullfilment. I heard a few complaints about ability to get a promotion, but I don't think I could personally judge if this was really a company wide problem or an isolated incident or two.