How good is the Saab AJ-37?

I just recently read an article that says the AJ-37 was once evaluated by NATO against the Mirage F1 and the F-16 does any body knows the results of such evaluation.

Some Articles have compared the Mirage 2000 with the F-16, claiming the F-16 and Mirage 2000 are relatively well matched.
The AJ-37 Viggen nevertheless is a more interesting aircraft being quit mysterious i have no idea how it is as a fighter?