The Navy's ERP system has already been "deployed" at certain commands such as NAVAIR and SPAWAR, so it isn't like they have spent this money and not produced a product. The system has issues, some of which are outright bugs (e.g. losing employee time sheets), some are poor design choices (e.g. the purchase request part of the system had issues with $0 line items on orders, previously we had to put in $0.01 to make it work), and some are dumb policy choices by the DoN or the local command (e.g. we are not allowed to use the built in leave request system, we still pass around e-mails or signed PDF documents).
Overall it is an improvement over the systems it replaced - for me that was a series of in house systems that essentially emulated the original WANG environment and re-used COBOL code. It does make it more difficult to fix things and I still believe the system has a hard time working with the DoD's "accounting" system i.e. different colors of money, lines of accounting, money that expires, etc.