There is an excellent article in Gary Heerkens' Generating Value [1] column in this month's PM Network. The opening paragraph reads:
"Which is better: a project that runs on time and budget and meets its objective, or a project that runs late and overbudget but overachieves on cost savings that have a "change of life" impact?"
For me this topic is SO on point! Every project is an investment, and the value we get out of the investment, all else being equal, is THE key metric.
If you're a PMI member, have a read.
Fraternally in project management,
Steve the Bajan