I have been testing out lots of different blades over last few years for cutting amtico / Karndean When I was on the Karndean course we used one called proflor I think which were titanium tips and were best I've ever used. I managed to get a few boxes but can't get them anymore. They cost about £30 a box. Any one used them. Since then used Stanley which are crap and now on Mozart which are better but no were near as good as the proflor ones. It's all in the tip
The best ones for the money I ever had were Janser Green box but are quite hard to get hold of. I've just discovered they're available at one of this forum sponsors RWS for £14.50 / 100.
Probably best to go for the Janser ones also from Germany is "FLOORFIT" blades apparently the German steel (solingen) is better than british.