To me, the job of mouthpiece cushions is to protect the mouthpiece from your teeth and your teeth from the mouthpiece. To this end, these cushions do a perfect job. The feel of the rubber is very neutral, yet firm. The cushions adhere to the mouthpiece without issue and stay on without a problem, at least on one made out of rubber. The glue is easy to clean when changing a cushion.
I practice daily and have only had to change the cushion on my mouthpiece once during the last 6 months or so. That was mostly because I had to wash my mouthpiece, which washed off some of the glue. Otherwise, the cushion was still in good and playable condition.
I see no reason to invest more money in mouthpiece cushions. These ones are very good for the price and do their job perfectly. I have no complaints.