Although there are teething issues, for US allies the unit the F-35 is attractive due to a unit cost which is lower than any of its competitors (such as the Eurofighter Typhoon).
For domestic use, the F-35B STOVL jet used by the Marines is a dramatic improvement in range and capabilities over the Harrier.
The F-35A/C are less of an improvement, but I would by no means call them a failure. It's easy to criticize a program due to cost overruns and mismanagement, but that doesn't mean the end result is bad. At the very least it's a sunk cost now, so we'll just have to deal with it.
For domestic use, the F-35B STOVL jet used by the Marines is a dramatic improvement in range and capabilities over the Harrier.
The F-35A/C are less of an improvement, but I would by no means call them a failure. It's easy to criticize a program due to cost overruns and mismanagement, but that doesn't mean the end result is bad. At the very least it's a sunk cost now, so we'll just have to deal with it.