Ask HN: Experiences with product consultants?

Has your company hired a consultant to help with product strategy, direction, process, or research? How did it work out?

I'm an engineer turned product manager, and have recently been advising a few companies, mostly startups, on how to launch faster, focus on high-risk assumptions, and put learning into practice. Some folks get it and value what I do, but I see many glaze over at the idea of any consultant who isn't writing code.

So I'm wondering if anyone would like to share experiences - positive or negative - where you hoped to get product help from a consultant.