This user has no status.
In effective play? What does that mean? I've actually had multiple professional players tell me they feel there are significant differences both in feeling and output shot quality, and I feel the same way myself having done side by side tests. For one, there is less quality, speed and spin with MX-P in the majority of range of shots. Do you have similar experiences suggesting the opposite or are you just spouting off something you read on forums?
No, my experience tells me that "all" players' ability to judge "quality, speed and spin" is biased and unreliable.
Yes, I do agree with you that they feel different, and in this area everyone has there own preferences which becomes narrower as they try more stuff. My experience in this area tells me that the slight difference in feel makes no difference in shot quality. As soon as you take your mind off "XXX-replacement" to "how to do Z with X", most modern rubbers are more similar than different.