https://motherboard.vice.com/en_us/article/wnjvb9/the-us-air...
The knife is pretty good and keeps its edge, but you can get a knife that's larger and locks. The can opener works great, but it's miles behind an electric can opener. The corkscrew never failed me, but it's not as comfortable as a two-step lever corkscrew. And so on.
Anyway, I think the analogy still holds. Any system that's built for multiple purposes will lose out to another, more specialized system built for a single purpose. Of course, this more specific system cannot perform all the other tasks.
This is the main reason this program was massively over budget and didn't meet expectations.
By trying to create one airframe for three very different sets of requirements, they significantly compromised the performance of all three variants. In particularly, the STOVL requirement for the USMC meant that the Air Force and Navy would end up with an airframe with worse aerodynamic performance and worse radar cross section than if it didn't have to accommodate the lift fan for the F-35B.
The whole idea of the JSF was to save money by featuring 80% parts commonality between the versions. Instead, it only has 25% parts commonality. This resulted in much, much higher cost than anticipated.
With further development and time to work on tactics, the F-35 will probably be fine on the battlefield. But the military could've ended up with far more capable platforms had they heeded the lessons of past procurement failures like the F-111, rather than doubling down on them.
I'm saying you can't easily compare two combat aircraft. You have to be very specific when doing so.