Thank you for your question.
Sharpal diamond plate is my newest addition. Got it a few days ago & haven't used it yet. I'm still working off of the yellow & red plastic based plates, moreso these days on the S SATC plate, & on the rods (Dexter diamond, fat ceramic). The buffing wheel sees some runtime when I'm looking for a very polished edge to test vis-a-vis a toothy edge.
So no assessment of the Sharpal yet. I snagged the Sharpal based on YouTube vid from Outdoors55 where he found virtually no grit contamination on the 1200 fine side (i.e. large irregular grit particles, typically migrated from coarse side by handling in manufacture I suppose). According to his reportage, such contamination is very common. So finding such a pure consistent grit size is a rarity.