Negative, I have worked with lots of ex-Impac ppl, and they all say that it is a bit of a meat factory - you work on a self employed basis, which is consultancy speak for "if there's no work, you don't get paid". I have heard of many jobs that have been buggered up by them (S & N foods?) - mainly due to greed apparantly - they simply focus on selling manweeks and will tell a client anything to sell a manweek. Approach is highly inflexible too, which is a very outdated way to implement nowadays.
On the positive side, the training is tough and disciplined, with Impac analysts among the best (no I am not). And you know where you are with the company, (more than can be said for most), since you are a number, someone who's job is to deliver the goods, and if you don't then it is goodbye sooner rather than later. Not my cup of tea, but can be a good eye opener for the young and strong.