This is only the second heel cup I've tried, and it's a winner. Nothing looks like it could be better.
Several years ago I'd tried another brand of heel cups for a problem with the fit of some of my shoes. It was was worse than no solution. They were too small (size 14 shoes). They would not stay in position inside my shoes, sliding to one side or the other as I walked. I was disappointed with the whole concept of heel cups.
Now I have plantar fasciitis. Tuli's Gel Heel Cups appeared to be worth trying, especially since they come in different sizes. The Tuli's heel cups stay in place pretty well. (I'd have to say they slip a little, just because my feet are wide in the front and narrow at the heels. There's always too much room at the heels of my shoes, but YMMV.) The shock absorption is outstanding, and they seem to reduce or eliminate pressure points inside my shoes.
I bought two spare pairs so a.) I have them on hand when I've worn out my first pair, and b.) my order qualified for free shipping (nice bonus). I recommended them to my niece, a dance team coach. She bought a pair and says, "They're AWEsome!"
Meanwhile, I found some great stretching exercises on the Web and added one of my own in hopes of eventually eliminating heel pain. I'd love to wear shoes without heel cups again, but in the meantime, this product is the only one worth walking on.