An interesting comparison:
https://nordicdefencesector.com/en/article/gripen-e-vs-f-35-the-wrong-question-to-ask
"There are many ways to detect an aircraft. The most common is a fighter radar (X-band), and stealth is a clear advantage there. It should absolutely not be understated that the F- 35 has a significant advantage in reducing enemy detection range, especially against older or less capable radars. The reduced RCS (0.005 vs 0.5 m2) means around a third of the detection range if you do the calculations and the stealth works optimally. It’s easy to think that detection range would scale linearly with RCS, but there’s actually a r4 relationship.
However, to fully benefit from stealth, you can’t use your own radar—doing so is like turning on a flashlight in a dark room. Even if they don’t see the flashlight itself, they know exactly where it is. This means a stealth aircraft in stealth configuration can’t see others unless someone else provides that information via datalink. And both sides can get that information from long-wave ground-based radars, which see stealth aircraft just fine."
"Infra-Red Search and Track (IRST) has advanced massively in the last decades. It’s a
passive sensor detecting infrared radiation, i.e. heat. Aircraft are hot, especially against the cold background of high-altitude air. Today, IRST sensors can see out to 100+ km, and both Gripen E and F-35 have them. But what matters is whether
the enemy has them, and they do. China and Russia have invested heavily in IRST, obviously in response to Western stealth reliance.
The enemy can fly with silent radars and use IRST to detect targets. Then it becomes a competition between IRST capabilities, and here it’s hard to say definitively who’s ahead."
"A large part of stealth capability comes from the radar-absorbent coating. Maintaining it is expensive and time-consuming. That reduces aircraft availability and increases fleet size requirements. Internal weapon bays also limit payload. The moment you hang external stores, stealth is largely gone.
A stealth aircraft carries that burden through its whole lifecycle. As mentioned, the advantages today are already smaller than in the 1990s, and they risk shrinking further. The F-35 is expected to serve for at least 50 more years, and it’s unlikely that stealth will remain decisive that long. The airframe is what it is, optimized for RCS rather than aerodynamics."
"In terms of range, Gripen E generally wins, but largely because the F-35 can’t carry external drop tanks without losing stealth. If you drop the stealth requirement and use external tanks, the ranges become comparable.
Once in the combat zone, avoiding enemy missiles requires sustained high speed and short bursts of acceleration before
missile launch. Here, Gripen E has a clear advantage. It’s 10–20% faster overall, both in max speed and on dry thrust. The latter usually matters more, since reaching max speed (Mach 2.0 for Gripen E vs. Mach 1.6 for F-35) is impractical in real combat. Flying Mach 1.2 instead of Mach 0.97 is akin to maintaining 20% higher running speed in soccer. This matters especially in DCA/OCA missions."
So, in air defense and air policing missions the stealth is not that relevant, but readiness rate and the speed of Quick Reaction Alert might matter more.
