I'm considering the same, but I recall reading something someone said while I was in uni - "Why would anyone want to be a consultant when you are mainly brought in for the 'gone to shit' situations?"
Getting a situation from 90% optimal to 91% is very difficult and produces an improvement few care about.
Getting a situation from 20% optimal to 50% is usually relatively easy; getting to 75% is a giant pain, and either result will get you hailed as a hero.
You also deal with the politics with the disengagement of an outsider, and you're gone before it can suck you in too deep.
Any thoughts on this? Is there any difference?