What does JAS-39 offer over F/A-18 or F-16?

I’ve seen JAS-39A-D lumped into the Generation 4.5 crowd along with Eurofighter/Rafale/upgraded Flankers?

So a couple of questions?

1. Is JAS-39A-D 4.5 generation or is it really 4th generation?

2. Other than being cheap to operate, what other advantages does a JAS-39 have over upgraded F-16 or F/A-18A-D?

3. In terms of performance, is JAS-39 even comparable to much heavier Rafale and Eurofighter?