I used mawk a long time ago, but it became stale. Last version I used, I believe, was 1.3.3. It was excellent - fast and accurate. I crunch a lot of data, and it always outperformed gawk. I migrated away from it when it would no longer compile on a Linux system. As I still had gawk, and gawk was fast enough, I left mawk behind.

Now I'll have to see if I can get it to run on OS X. Hmmm... ;)

UPDATE

It's available on MacPorts. It should be on my machines tonight.