I usually really like to loop hard from close to the table using the backhand and I feel that with increasing tiredness I am making errors that probably would be tolerated better by a softer sponged rubber.
From the point of view of the philosopher you might not actually have a rubber problem but a fitness problem.
I do recognize this effect myself towards the end of a club night my movements are not as fast, my arm is not snapping forward and upwards as in the beginning of the session.
Already about 10 different "best rubbers" have been suggested in this thread , you would really have to buy and try them all but work on your health and fitness can be free.
Best regards
Lodro
P.S. I used to be a philosopher and a poet - but now I am just a bum.