Pros
The large majority of coworkers are intelligent, easy going, and all-around decent people. On average they seem to be less pretentious and more down-to-earth than what I've seen at EY or especially PwC. Deloitte wants to do things right, and the firm's culture is good though it still suffers from its size like any huge firm. The benefits are pretty good- especially the 5 weeks vacation/sick time that you can roll over for a year, and that they'll buy from you when you leave. Healthcare, dental, phone, $500 fitness subsidy are all good too (401k is not the best though- 1.5% max match w/delayed vesting). DU is also nicer for annual trainings than a random hotel conference center somewhere like the other firms use. Obviously it's a good name for the resume. Job security is excellent for at least your first 5 years if you don't do anything stupid, and job offers for decent industry positions will come to your inbox all the time (especially after 2 years when you are promoted to Senior). If you want to work in accounting, internal audit, financial reporting, etc for the long haul then you'd be crazy not to start in Big4 for 5 years. If your plan is to jump from audit to something else outside of accounting (consulting, financial advisory, MBA, etc), you'd probably be better off just starting outside accounting. There's not as much internal mobility across functions as some recruits seem to expect. I would choose Deloitte over other Big4 firms unless I wanted to work with a particular client or industry that wasn't Deloitte's strength in that city. PwC has a slower promotion schedule to manager, and KPMG is less desirable all around. EY is fine if you like tech companies and excess we-pretend-we're-cool enthusiasm.
Cons
Bonuses for junior staff are basically nil, and ratings for junior staff are likewise worthless. There is little opportunity to differentiate yourself from your peer group within your first 3 years- top performers don't get anything that bottom performers don't (this changes after 4 or 5 years, but most don't stay that long). There is also very little flexibility and choice on staffing. If you get a particularly nice or influential mentor then you might be able to switch to a more desirable client or project, but most of the time it's simply luck of the draw and some of the clients/teams are very undesirable. In my peer group, some people had 45 hour workweeks for 10 months and 60 hour weeks for Jan-Feb (a light schedule) while others had 45 hours for 4-6 months, 60 hours for 2-4 months, and 70-85 hours for 4-6 months. Public accounting comes with the expectation of busy season and obviously the firm can't always predict extra work needed on a certain audit, but there isn't any mechanism in place to meaningfully reward those who get the short end of the stick on staffing assignments. One team that was working 8am-2am for 3 months got $200 Amex gift cards or something at the end as a "recognition gift" and then the same review rating as all the others; it was like a slap in the face. At least some part of compensation should tie to billed hours, even for junior staff.