The things I wonder about the F-35 are how long the stealth advantage is going to actually be an advantage, single engine, and how good it actually is as a fighter.
If I was going to consider an alternative and money wasn't the biggest concern, the Typhoon might be my second choice, as I think the Typhoon might have the edge on the F-35 as a fighter (and air defense is going to be its primary role isn't it?), and it has the two engines. The Typhoon has a higher top speed, a thrust to weight ratio of over 1.0, and the ability to supercruise (F35 claims a short supercruise ability) so the Typhoon will have an advantage in long range BVR as well.
I don't know if the Typhoon matches the F35 for air to ground but I've read that the more recent Typhoons improve on this.
However longevity and cost are factors too, Typhoon is older, and while I think initial cost of Typhoons are cheaper than F-35's, total cost might be pretty close.
Too bad can't have both
