Proudfoot have a tried and tested methodology for selling their services, which many enlightened people would call tired and old hat. There is a very good reason they have a high turnover of personnel, and yes, there are still some great people there, but many more have left. Business itself is fundamentally unsound - they rely on the big sale, big client and big projects - which they have to since there billing rates are rediculous. If you don't mind hire and fire, like the possibility of being posted to Zaire if that is the only place they have managed to sell something etc then Proudfoot is the place for you. Frankly, it is miraculous any CEO's are stupid enough to fall for it any more.
As for Celerent...great French MD. However, their set up is quite restrictive from a personnel point of view. They have 'sectors' - if your main experience is automotive, that's where you'd be (if they have work), and you would be up against very experienced sector speicialists when it comes to advancement. Once in a sector, difficult to transfer - Celerent is notorious for 'fiefdoms', and is highly political.
So...who to go for...mmmm...go for the cash, get yourself trained in implementation methodology (i.e. make your mistakes fast) then move on...become a freelance...join the contractor section on top consultant...earn more, be free...but above all...deliver to your client.