I currently use both these site tracking tools on my blog. One of the biggest differences I see is that in Active Meter I am able to get real time data. Whenever there is a visit on the site, the active meter shows the visit – also it includes if the visitor was unique or returning.
How the visitor was referred to my site, the location of the visitor and also if they used a search engine to get to my site – what was the phrase they put in the search engine.
Getting all this information real-time is awesome; I guess this basic analysis helps a lot.
On the other hand with Google Analytics there is more than a 24 hour lag in getting the report. I looked up this morning and still June 2, 2008 report was not available. In this day and age, I think we should be able to get a lot more frequent reports. At least some basic information should be available real-time.
I also use Pagealizer which provides the scroll length, click time, page view length etc. and all this information is real-time as well.