Second this. I've been using it for a couple years now. Works really really well.

The time that you've been given to familiarize yourself with their environment is gone. You have found a tonne of inefficiencies and know exactly what you need to do to clean, automate, improve etc...
BUT
Now you have to start doing the work that 'the business', the part of the company that makes money, you find yourself taking short-cuts and applying the same types of band-aids. It is the curse of all IT professionals!