Morticing Chisel Sharpening - HSS or Abrasive?

I'm looking for a Morticer bit sharpener and it seems they fall into two catergories,

HSS cutters (like carbatec- Mortise Chisel Sharpening Kit : CARBA-TEC )or Abrasive impregnated grinders (like this Diamond Cone Mortice Chisel Sharpener - Morticer Accessories - Drills & Morticers - Wood Working | Axminster Tools & Machinery)

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Any preferences or not much in it?