I work for Deloitte in the UK as an SC. I'm not in operations but have worked closely with the guys from there, and having been at the firm for 5 months can report that I'm a pretty happy camper.
+ Generally good work/life balance (though with exceptions)
+ Great people (far more affable that I've found elsewhere, very bright)
+ A genuine focus on high-value strat-type work
+ Interesting range of clients
+ Great brand to work for, with cross-competency exposure and opportunities
+ A good vibe, with an opt-in or opt-out social life (I've seen no pressure to get hammered 5 nights a week with colleagues)
+ A UK-focused culture, no silly American 'be a tiger' adverts
+ A true partnership, not an outsourcing-focused PLC
- A client list in some grim parts of the UK (esp. public sector work)
- A relatively bureaucratic culture
- Salaries not as high as ACN, for example
I really rate this firm, having worked at other big-5 consultancies.