AWSTATS is a useless overall program for website analytics. AWSTATS is a statistical software, and extremely inaccurate, as it just measures everything, including bots. Google provide analytics, which are far different from statistics. Analytics allow you to track your users through your website, shows you your strengths and weaknesses, so you know what not to touch, and what needs improvement, ie. 90% of people hit this page and stay for x time to read it vs. 90% of people hit this page and leave immediately.
You cannot tell any type of analytical analysis from AWSTATS.
Whilst there are better programs that use your raw log files, which provide better accuracy than Google could, they are also expensive vs. Google is free. If you use Adwords, Google is directly tapped into their own software for tracking.
It does not add up your stats across multiple years. Awstats does not tally up the amount of keytypes of the keyword. It does to an extent, but not as clear as Google. On top of that, Awstats while a great program for stats tracking, it's kind of confusing to see exactly where your visitors are coming from. Google provides a clear, concise look at your traffic source, and your exits.
Is there a way for any of them to track by which forums / subforums? e.g. xf.com -> suggestions statistics vs xf.com -> offtopic forums.
Google allows for tallying up pageviews for each forum/page, whereas, awstats does it within' limitations. It doesn't tell you the percentage of visitors are new, or returning. It doesn't tell you a lot about the page. On the flipcoin, Google doesn't tell you where the visitors are coming from on each page view. Not a lot of server software technologies do. Its something that needs solving.