Yeah, I think it was worth it. They completely replace the stock metal ring / O-ring combo. I think the outer edge of them are still metal, but they are completely enclosed with rubber and have grooves on the sides to help with sealing. I completely messed up one of the stock metal rings when trying to pry it out, so it was a good thing that they replaced it...!!!
As a side note, if you order online through them, it automatically will charge you 6.00 for shipping. They adjusted the shipping accordingly when I actually recieved them.