AV Week has a good article on challenges facing air forces that select the F-35. It also mentions F-22 challenges.
I would also like to add:
1. The fact that the F-35 will not fit into existing operations budgets of air forces: this means more parking than flying; and simulators as the tire patch.
2. The fact that with all of its faults, the F-35 mission availability is a flying question mark.
3. The fact that the design is obsolete and will not be able to take on emerging threats. And, that some existing legacy threats can detect it, and kill it.
This leads to the fact that air forces that want the F-35, risk dooming their nation to a loss of air supremacy.
Historically, that has never worked out so well.
