These are one of those tools that every woman needs. It's a rare woman who doesn't own a pair of beautiful but horribly uncomfortable shoes. These are great because they give you some cushioning in the sole of heels that are otherwise like walking on cardboard.
Having said that, there are some downsides. They are sticky - which is good for making them stay in place, but means they can take a while to get in the right spot (but once there, they stay there). The other downside is that if you have wide feet like me, this adds to the bulk in the front part of your foot, making tight shoes tighter. Having said that, this could be an advantage if you have skinny feet (I wouldn't know, not having that problem!).
End result? If you don't have them, you probably need them in your life!
I loved this product - it reduced the pain from my shoes. It's not as effective as a full insole, but because it's transparent it can be worn with any shoe - even strappy sandals - without being too obvious. I do find that they eventually wear out/get grubby. Also I did have some issues getting them to stay put in some shoes with a silk-lined toe.
Tips: * Don't put these into tight shoes. It raises your foot up so that even though you may get less pain on the balls of your feet you end up with blisters on the tops of them.