Well, I just couldn't resist it. It looked shiny, so I bought one and it arrived yesterday. At first glance, it looks of quality construction, and is cheaper in price to the Olsson ruby (3D Prima's site list their nozzle for £53.91 and the Olsson ruby for £89.55).
Naturally as I have the iSeeing iMicro Q at my disposal, I put the 3D Prima nozzle under it for closer inspection, and this is what I saw:
A few inconsistencies in the gemstone, but nothing that should affect print quality to any great extent. There's also some debris (possibly) in the bore, but with any luck that should be pushed through and cleared once filament starts running through it.
What's next? It'll be installed on one of our Prusa Mk 2.5's either this week or next week, and I'll be printing some PLA models as well as some NylonG or PA-CF models with it. Once it's been used for about a fortnight it'll be cleaned off and put back under the iMicro Q for another inspection to see how it has faired. However, this won't be a massively fair test to put it up against the Olsson rubies, as those were installed on the printers for many months, and were in use almost continuously during their installed time.