they all run with GSManager.
One of the main problems is that the development of such a page needs time, much time.
The most stats pages are based on two parts:
Both of them need much time to check if it works (is the kick, ban, stored correctly with the correct id? Does the online time tracking work? ...)
I can't speak for C4S or SFS but it took me many months to write the plugin and the website, because I only worked on it in my free time.
So you may ask:"Why does he not just release the existing files?"
Of course, I would do it (because I like the idea of open source stuff 
) but there is a huge problem: It's incompatible 
I started the programming of the plugin when Manuadminmod 0.12 got released. The MAM doesn't have a good database design to use it with multiple servers. So I created my own stuff. The GSM has a much better database layout which could be a very good base for a new stats page / admin panel because it has super cool features directly build in the core.
Unfortunately we haven't that much time. So we try our best to fix the problems of the GSManager before we start to develop new features.
The C4S page also does not run with a stock GSM, it also took me months to write only the page and it is not yet finished...
