Sounds like a decent deal to me.
The US gains massive cheap R&D and real world tested capabilities for a fraction of the price it would pay domestically.
Now you could argue about the moral implications, but money wise it's a great deal.
"...To sweeten the deal, Lockheed Martin said it would buy parts and systems for the F-35 from Israeli companies at a cost of $4 billion..."
What is funny thing to say, since Israel, unlike the other nations, never supported the development costs of the F-35 program :-)