Sometimes it depends who you ask; I found that hands-on people on the ground and SMEs tend to be very negative about it, for personally valid reasons - it's a lot of work, it doesn't go smoothly, and it disrupts and changes what and how they do it.
However, there are quite a few ERP implementations where the top-level stakeholders feel the results are worthwhile the disruption and pain, and from that perspective it "went well" - the business objectives were overall met, whether it be capabilities or speed or reporting or integration/centralization or headcount or complexity reduction, all of it ultimately boiling to money at some level...
Only the top-level stakeholders felt the results were worthwhile the disruption and pain -- that they did not suffer.
But have you ever heard of one going well ?
As in, not just worthwhile to a tiny minority of the people on the top?
Yeah I bet it makes stuff more efficient, but clearly there's a disparity between the people suffering "disruptions and pain" and the ones who ultimately feel it has been worthwhile.
And maybe, just maybe, what is right for the business is bad for the majority of the staff. At least in the short term. I know that is a bitter pill to swallow, but it is reality.
Perhaps an example more palatable on HN would be Uber replacing all its drivers with software. Clearly better for the business.
however, not once have I ever heard of an SAP implementation going well. It's a massive undertaking and takes total commitment from so many different people and roles in an enterprise. You need genius PMs and BAs along with a genius client team before you even talk about the actual technical people.