Pros
I am an ex-big 4 consultant (spent 4.5 years in one). Protiviti is a very small firm. I cannot stress that enough. It's not a big 4. If you crave the glamour that comes with the big 4, Protiviti will lack it. That being said, not being a big 4 is also the best thing about the firm. No independence issue means more clients, more agile, much less red tape. Plus if you are a high performer, a lot of attention will be showered on you. Upper management is very accessible. The training program is light years ahead of big 4. Leadership here understands that they are competing with some very big names in the big 4, so it is encouraged to hustle harder. So it's easy to create your identity here. Most days I feel like I am working in a start up. Very exciting.
Cons
Pay isn't very competitive. Since it's a small firm, you'll have to end up doing projects that aren't in your wheel house. It's not a big deal but for those that don't like to deviate even a little, that can a nuisance.