Pros
High prestige (particularly in corporate practices) / working on major deals. Reasonably strong exit opportunities (again, particularly from corporate practices). Partnership prospects are actually decent if that's what you want and you're willing stick around for 10 years and work 2500+ hours indefinitely. Counsel is also a genuine option. Culture that requires people to be decent and polite. May vary by group, but mine has little face-time expectation. At least some successful associates often work from home. Lockstep partnership comp gives groups incentive to work well together, and partners incentive to share resources efficiently. Good for associates not to be fought over by partners who have their own eat-kill comp in mind. Good client contact for talented and trustworthy associates (depending on group). Comp and parental leave are at market. Fine cafeteria with discounts. No minimum hours for on-market bonus. If your department has a slow year, you don't have to worry about losing comp. (But also no extra bonus if you have a heavy year.)
Cons
Space is broken. There are sixth-years who are still sharing offices, and large meetings are nearly impossible to schedule. Way off market, and partners seem oblivious. Management appears to have head in sand; seems to be waiting for extra space to magically open up in our cut-rate building. Departments vary on treatment of vacations. Some give coverage (but often only for longer trips), some don't. Weekend instant-availability expectations worse than average biglaw. Process management is oddly weak given the caliber of people, but maybe par for biglaw. Not a point of emphasis and it shows. They have a training for 1/3/5-year associates, but don't do enough to free people up to attend. Partners who came up internally don't have the expertise to improve matters. Good pro bono opportunities are there (especially in Lit) but not as integrated into the firm's work as elsewhere. (Separate assignment process, little partner involvement.)