Been using these for about a year and a half now and the grip they provide is soooo nice and they've held up nicely. No peeling of the rubber, and they don't get dirty very easily at all unless you eat and play at your desk (I don't, that's a bad call lol). I highly recommend these for the $15 I paid. Absolutely worth it. Also, I decided to swap my ZXCV for the right, up, left, and down arrow keys respectively since they somewhat resemble the letter they replace and also to have more rubber keys in use.
Edit: Over 2 years now, have used them every day since I've gotten them. Even after all this time with long gaming sessions and schoolwork, they're identical in feel and look to when I first got them.
Would recommend to a friend.