I must say, that I misjudget Loki Rxton III rubber somewhat. When I assembled a racket with it, its sponge was really dull "out of the box", so I just put it away for several weeks, but today I tried it again, and now it has better feeling and significantly more speed, so it is not nearly as bad as last time - average throw at most, but easy to use now.
The same goes for another racket with Meteor 575 short pips - while that isn't felt dull, but it seemed like if it had a dampening sponge, and it was difficult to use. Now I easily do my shots (including topspins), almost what I want.
After seeing this happening, I may rethink about getting a pair of Rxton V, which I did not bother previously.
I will have more testing sessions with Arthur China - so far I can say, that it performs similarly to Victas Triple Extra. A similarity is the rubber topsheet hardness compared to the sponge hardness (softer, but less of the magnitude) - differences are that the rubber needs somewhat more active strokes to be used effectively, but it is also somewhat more tacky.