ok. let's do some simple math.
expiring today, the bestskinsever is $6+$2 for shipping=$8 (the regular price is $8+$2 shipping)
invisibleshield costs $25 with free shipping.
also, WHO NEEDS A WARRANTY? this isn't something with moveable parts that can break easily. this is a piece of semi-permanent film. also, even if you get a replacement, there is a shippping charge of $3 EACH time http://www.shieldzone.com/guarantee/index.html
so getting 2 invisible shields costs $28 and 3 shields costs $31, and 4 is $34, and 5 is $37
getting 3 best skins ever costs $24 because it is free shipping (if you buy 3 or more skins at once), and 4 skins is $32, and 5 skins is $40
So just working out the math, you'd have to replace the skins FIVE times before the invisible shield is more economical. not only that, you have to wait for the invisibleshield to be mailed to you and you have to mail the original one back each time. more trouble and hassle.
financially, any one who has done the math and read the details would know that the bestskinsever is a better deal.