I search google and found a lot of info between the two. It says that awstats usually inflate the number of users.

However, mine is the other way around, one of my site, Analytic reports 23,000 visit, but on awstats, only 17,000. Why is it so much different between the two? Especially awstats is usually consider more exaggerate. Which one should I believe now?

I thinks its always better to use more than one webstat program as they all will report the numbers differently.

For more detailed statistics, I would recommend statistics software like Smarterstats or Deepmetrix. Many of the customers setup google analytics and prefer it over awstats.