I've purchased the Insivible Shield twice and I had both good and bad experiences. First time I got it for my 2nd Generation iPod. Shipping and costs were fine and I just had some issues by the time to install it on the surface, there're some mistakes that started to detach with the time, but it was just my fault. The screen visibility, surface protecction and pad sensitivity work quite fine, even against keys contact, fall accidents and so on.
Then I ordered again for my girlfriend's 3rd Generation Nano iPod and first time ti just did never arrive. We claimed it and they re-send it, and so this time I took special care to put it on, put seems those rounded corners of the 3rd generation are just not made for such thing. There're some "white spaces" without any protection on the corners and that's a pity.
Anyway, the shield works great and it's worth the price, but take care when you put it on and check up first the design for your specific dispositive.