In reply to andyathome:
Well I work on "grabby" to mean that the plate tends to grab the rope and partly lock when I´m feeding rope, that´s annoying and means the belayer will be paying more attention feeding than actually belaying. Personally I just put that down as a fail.
Then there´s plates with more braking power related to the hand grip from the belayer and plates with less power which is ultimately what matters, some slick plates have suprisingly more braking power than the grabbier ones.
Testing a plate as a one-off item is effectively impossible for a test lab which is why there is no official test but the rest of the world uses effectively a comparison test where we have a benchmark device and then compare how different ropes and plates work compared to this. There are tests out there from various companies which cover many devices but it´s a thorny subject publishing them, as there is no official test an aggrieved company could reasonably object that the method used was unfair. Posting on a forum on the other hand is just an opinion.