Pros
Deloitte is recognized as a reputable firm in the US. The "value proposition" for joining Deloitte is the opportunity to gain more experience per year than one would get in industry. That's a politically correct way to say that you'll work ridiculous hours.
Cons
The firm, under the banner of "One Deloitte", is remarkably divided and rife with internal competition among practice groups. If you find yourself working for the wrong partner or practice, you will not succeed. Deloitte promises to build your skills and industry expertise, but fails to execute. The Deloitte propaganda machine touts the firm's commitment to Mass Career Customization and instead delivers round after round of Mass Restructuring (p.c. for layoffs). The partnership admission process is nothing more than fraternity hazing ritual resulting in a top-heavy organization of underwhelming partners who fail to produce new business.