so many of them are terrible. have just taken the latest awful one off my phone as I was sick of having to bash everything 3 or 4 times hard just to get the touch to register as the screen sensitivity through the protector was so bad.
I did have a decent one before (which did its job and died in the line of duty saving my phone) but it's now out of stock. if I just pick one at random I could get a bad one again, but I know good ones exist.