HDS End Mill Tools?

I just bought a couple of end mills from RS Components. They are made of HDS (Hardal Supra) which they say is a new alternative to Carbide. Does anybody know about these and what it actually is? Good or bad?

http://docs-europe.electrocomponents...6b80f8a41d.pdf

I was looking at them last week and wondering the same thing. Can you let us know what there like when you have tried them out?

I've tried a 6mm 2 flute in Aluminium and Acrylic now. It's average for acrylic, but brilliant for aluminium. :) It's far better in alu than the 1 flute solid carbide cutter. At least for me, in my mill it is. I've ordered a ripper of the same brand to try (£12 on RS). I'm hoping this will work really well as I think the main weak point of my mill is chip extraction.

Thanks.
I will get a couple and try them out.