I know your question is directed to the ModX team, but I couldn’t help answering.
I used to have reinvigorate on my website, been one of their beta testers for 6 years.
It is quite good, specially the latest iteration. Very, very well designed and some pretty nice features that you can’t find elsewhere (heat maps are quite cool -
http://cdn.reinvigorate.net/_images/screens/heatmap.jpg). The bad thing is, now that they’ve released it to the general public, they began charging for the service. I’m not saying it’s not worth it... but if you have a personal / very low traffic website as me, chances are stats aren’t that important to pay for.
I’ve changed to google analytics since, and I find it equally functional, even though not so nicely designed.