Dusting off some old copies of "Jane's" I see that the 1980-81 edition gave:-
Viggen -
Tactical radius with external armament
Hi-Lo-Lo +1000 nm
Lo-Lo-Lo + 270 nm
Jaguar
Attack radius internal fuel only -
Hi-Lo-Hi 460 nm
Lo-Lo-Lo 290 nm
Attack radius external internal fuel
Hi-Lo-Hi 760 nm
Lo-Lo-Lo 495 nm
Ferry Range -external fuel 1902 nm,
Looking at the numbers I think the Viggen could fly further and faster and had better field performance but the Jaguar could carry a much wider and heavier weapons load. Not surprising as the British & French had "proper" interceptors as well whereas the Swedes had to have only one type to do everything.
Looking around I guess the nearest US equivalent would have been the A-7 Corsair?