Positive.
I joined the School in the congregation in 1966 and gave a bunch of bible readings and small talks, I have also read the Watchtower on the platform at the meeting in the 70's, said prayers at the meetings and taken the arrangement for field service and done the opening part in the service meeting been in demonstrations on the platform at the circuit assembly and spent hundreds of hours in field service talking to a variety of people.
20+ years later I was no better than when I started in 1966, probably worse. I got a couple of G's for my talk in 1966 and W's for the last few. I always hated getting on the platform and wasn't too keen on going into the Kingdom Hall. I don't like crowds. I am supposed to meet some friends and relatives at a pub later today before seeing a play and it's 50/50 as to whether I will actually make it into the pub.
One time my brother and I had a discussion with my parents about the benefits we felt the 'Truth' had made for us growing up and not getting in bad ways and bad association etc, My father and mother felt there was some input from the 'Truth' but also felt it was more their parenting as he could point to some who had even though raised in the 'Truth' had fallen into bad ways and I have to admit my father was never going to be easy 'Truth' or no 'Truth' He was a fascist before the 'Truth'
So on those two things I can't cite them as examples of how I had benefited positively.
The one thing I can say I feel that I benefited in a positive way is my praying. I am positive with it and I think that relates to being a Witness.