Some thoughts if I may chime in:
I bought the C12 Li a few weeks ago, to use at home. I have the C15 Li at work. They both work great though I do think the T12 is more comfortable to hold I appreciate the design of the C-series and I dislike the oversized battery on the T12 - it just makes it clumsy.
The CXS just found it's way home to me (if I had known it was coming I might have skipped the C12) and at first I was hesitant about it's versatility.
One thing that was a small concern was that the chuck will only allow for up to 8mm drill bits so if you wanted a 10mm drill you'd have to get one with the speed change bit end to fit it in the chuck. Bummer. But then I discovered that the standard chuck (of which I have three) fits... ...so no worries with that. The included chuck is smaller and I don't need more than 8mm it is the logical choice.
It is very light and powerful enough for most small tasks but I have yet to try it out for sheer power. Just now I will go and tear down a kitchen and will try it out with some bigger screws and see how far it gets. The C12 will supervise.
The angle chuck is flimsier than on the bigger siblings but it does the job - it will be used for small tasks in tight quarters anyway so I don't see a problem there.
Balance is very good, better than on the C12 I think. A little forward weight when the bigger chucks are attached but it does not affect the handling. With the bit straight in the machine it is very compact and it feels like the magnet is more powerful as I have not had the bit fall out yet (which it did all the time on the older C12) and when I was renovating some loudspeakers I really liked working with the CXS. Very tactile. The bit holder up front was convenient and the light was handy as well.
So far, no issues, will see in a couple of hours if it is too weak for some kitchen demolition though.
/ Henrik