Engines,
The fact that F35 is under public scrutiny is a positive as it offers hope that past failures are less likely to be repeated. Avoiding the mistakes of over-promising or under-costing, or whatever combination of them it is that results in too many military projects going off the rails must be best for everybody. The days when the taxpayer would just pick up the tab are gone and unlikely to return for a while yet.
..the key is how well they meet the KPPs and other requirements that the customers and the design teams have set...
Totally agree - getting it to work is the most important objective left to play for.
My opinion remains that it would be unwise to place firm orders for any version until cost, delivery and performance are much more certain.