New Counter
After over five years of using Sitemeter, I've decided to switch my counter to StatCounter. I had both running yesterday to see if I liked StatCounter enough to change. I do like it quite a lot, so I dropped Sitemeter from my main and archive pages. (My old style archives -- the ones that use the entry number rather than the title as the URL -- will stay under Sitemeter. Those are no longer accessed by the MovableType software and I just keep them around so that old links and trackbacks will work. I'm not about to go into all of those manually and change them to the new counter.)
The main reason I switched is concerns over spyware and adware cookies that Sitemeter uses. In fact, my workplace has banned Sitemeter for months because of this.
Also, I just plain like StatCounter better. The thing I like best is that you can create as many counters (or "projects") as you need under one login. You don't have to have a separate login and password for each counter. I will be switching my radio site and faith journal over from Extreme Tracking to StatCounter as well.

Definately going to link this up over at blogs4God.com - and perhaps cite it later this week over on HealYourChurchWebsite - as I think you offer a good and reasonable assessment, review and comparison of these tools.
I would also be intrigued to see how you compare these two to a tool such as Google Analytics.