Pros
Everyone is personable and professional. The culture is excellent. Seldom if never is there passive-aggressive communication from staff or attorneys. You feel part of a team, respected, and proud of your work.
Management is courteous and attentive to the staff. If you need something, your superiors will bend over backwards to help.
Cons
Staff members change job titles and functions on a regular basis. This could also be a pro because it keeps things interesting. If you work here, you'll learn a range of administrative/clerical skills.
A major negative in working for a law firm, however, is that there aren't many opportunities for advancement for staff. That's not so much a critique on this specific firm as it is a generalized statement about the legal world. Unless you're a lawyer or paralegal, you might never be promoted. By nature of the business, there simply aren't many upper-management staff positions that open frequently.
Lastly, the pay is not great for staff. Without a doubt, though, this is intentional on behalf of management to keep costs low and encourage staff to move forward in their own careers. It's a great place to work for supplemental household income or for young graduates/students pursuing education and opportunities elsewhere.