Pros
CapTech is what happens when you take a thousand people who have the experience of being "the smartest person in the room" and you put them all in one office together. This is a culture where people talk excitedly about technologies and development methodologies and where curiosity and innovation are highly valued.
After working as a permanent employee for most of my career, the variety of consulting is very stimulating.
Consulting opens up more career opportunities than working as a permanent staff member. To be promoted as permanent staff, you have to wait for a position to open up (and some of your managers were promoted not because they were ready but because they were the ones available when the last guy left - now they aren't going anywhere and neither are you!)
Cons
Internal support for employees on more difficult client assignments could be better.