The problem is more about internal applications that have nothing to do with the identity of the company itself. Personnel management, time tracking, accounting, and payroll apps suffer from poor quality if built in-house because they are part of the cost of doing business independent of what that business may be.
Our users were satisfied with RTS's planning results. The UI gave them some trouble. The major dissatisfaction with it was the difficulty in updating/maintaining the many desktops at our company and at our partners' offices. A year ago, word was that UPS was considering possibly offering RTS as a hosted service.
So, is RTS amazing? Well I haven't seen any papers from UPS computer scientists describing their novel contributions to the algorithmic state of the art. The UI is a bit clunky; users don't fall in love with it. But, it doesn't crash often and it does a satisfactory job solving a non-trivial problem, which is more than I can say for typical in-house enterprise software.