Pros
It's fun to work on titles that everyone has heard of and knows about. For the first year, it seems like a honeymoon for most people. It used to be a fun, rapidly growing company that gave tons of opportunities to anyone who had the initiative to grab them.
Cons
Blizzard is an old boys' club that favors the people that have been there forever, even if they're horrible at their job. There is a huge compensation difference between the people that were there pre-WoW versus post-WoW... often orders of magnitude difference 3x, 4x, 5x) for the same role. The base salaries don't have a huge difference, but the twice-per-year bonuses vary extremely widely. It's not common for a new hire (Sr. level or above) to have a bonus target of 20% their base salary, whereas a pre-WoW employee at the same level may have that target at 100% or more of their base. Blizzard now also suffers from a ton of red tape that makes it difficult to innovate and be creative. It seems like everyone who has wanted to build their kingdom has already done so, so many things that shouldn't need approvals now need several from different departments. Also, working 80+ hour weeks is part of the DNA here... so definitely come in expecting that.