According to this article on ESPN, it ranks the top fastball pitchers in MLB history according to year and for the current pitchers in baseball, Benitez was at the top, second only to Billy Wagner.

 

2000-present

1. Billy Wagner

2. Armando Benitez

3. Bartolo Colon

4. Kerry Wood

5. Randy Johnson

6. Mark Prior

7. Curt Schilling

8. Jason Schmidt

9. Jose Contreras

10. Johan Santana

 

Also, it ranked him as having the 7th best fastball between the years 1995-1999:

 

1995-1999

1. Randy Johnson

2. Billy Wagner

3. Pedro Martinez

4. Curt Schilling

5. Kerry Wood

6. Roger Clemens

7. Armando Benitez

8. Bartolo Colon

9. Jose Mesa

10. John Rocker

 

http://sports.espn.go.com/mlb/news/story?id=1822135

However fast it is, it certainly is fast enough to blow it by the guys at the plate.

 

Also- just having a fastball isn't enough these days. Penny has a tremendous fastball but you can't go back to that for every pitch. Eventually, someone is going to catch up to it and hurt us bad.

Yeah, he threw one 99 last night in the second inning, but it seemed like all he threw is fastballs really, but got the outs so works for me

Mando has a wicked fastball, but has proven more effective if he eases up a bit to get better location. His 92-93 fastball can be damned near unhittable when he is spotting it at the corners.