I have been using the kapex for a little over a year, bought it because I was building and installing a library with lots of mouldings. When the kapex showed up, I compared the stiffness or flex to my old 12" dewalt, the dewalt was stiffer, so I tried different cuts with kapex, all with great results, no deflection on any kind on any cut.
This is my fourth miter saw, I was a little worried about spending this much for a miter saw, but this thing is really far more accurate and versatile and than any of my other saws, no comparison if you do high end wood work, its a joy to use.
I made a zero clearance insert , although it is wider than blade now, probably from miter cuts, I have not seen the flex of the head show up in any cuts, I just did a big teak project cutting all 2x teak, cuts are still like glass with this blade.
I read some comments about the motor having problems, sounds like it might be some isolated batch, I hope festool would do a recall of them if they figure out that was the problem.