I love the ability to add custom data such as usernames to the tracking system using Javascript.

I run a few membership websites and being able to see visitor's usernames and track their actions that way is invaluable.

Yes, Clicky is more visitor centric, including tracking custom data per visitor, but plenty of good overview data as well. Plus the whole thing is real time, including goals and campaign tracking. Plus a very powerful API. Check out the Spy feature too.

GA does a number of things that Clicky doesn't, but the opposite is also true, as you can see by the handy dandy matrix you mentioned.

Disclaimer: I am the developer. :P