The software was part of a scientific computing system. We were an upstart product competing against a decrepit seventies-era product with an eighties-era interface. The competition was markedly inferior in performance and usability, but it was a known quantity and thoroughly integrated into the customer's workflow. By comparison our product was faster and usually more accurate, but less predictable. Our new bugs were much more disruptive to workflow than the existing product's old, well-understood bugs.