I don't have a Kapex. The only blades I have used in my ATF 55 have been Festoy blades.
I have used several makes of blades on my table saw (until I retired it) and my old Milwaukee circular saws.
I with the table saw and the Milwaukees, I was using a lot of reused lumber and so hit lots of hardware from form lumber and scaffolding. Hitting a nail almost always chipped atleast one tooth. For cutting form material, i just ignored the dings and used the blade until the blade started to warp.
When I no longer worked in construction and lumber used was much cleaner, I was introduced to Festoys. I still run across some used lumber (my son is in construction and does some demolition work). I am very carefull to examine for nails and other hardare. No matter how careful, I still occasionally run into a burried nail or screw with my saw or router (OF 1000 and 1400). I have yet to find a ding on any of my Festoy blades or router bits from any hardware collision. I am sure the same quality goes into Kapex blades as goes into other Festoy blades and bits.
Tinker