I mentioned that I was advising the guy I work with on plunge saws. He has used all my Festool gear and loves it including the TS. I sent him a link to this thread and his current view is the best combination would be Festool rails (plus accessories in time to build a system) with the Mafell saw. I can't say that he would be making a bad choice and my only serious reservation would be the lack of a plug-it cord on the Mafell. I have enough fun stopping an integrated hose and power lead from catching in all the wrong places. (for integrated read insulation tape used to fix power lead to hose)
It would always be possible to convert the Mafell using the Plug-it conversion kit ( Festool part no: 491144 ) but that would probably invalidate the warranty. It could also be possible to find out if Mafell would carry out the conversion themselves and still maintain the warranty.
If they could do the above my two remaining reservations would be the lack of riving knife (could someone explain the implications of that one?) and in the UK Festool's free tool insurance counts for a lot.
Festool - new tool in the event of theft
I still think Festool will be fine despite many learned FOG members believing that Festool got it seriously wrong with the upgrade. However they are not always that bright, they did design a rail saw with a scale that doesn't work with the rail.