I had an InvisibleShield on a Storm2. I would NOT buy another IS.
For one, they just seem extremely overpriced, especially compared to similar products (Best Skins Ever). Two,.. the edges and corners all started peeling up within a few weeks of installation (done by Best Buy). My phone was not kept in my pocket, or anywhere that would accelerate the corners peeling up.
Sure the "tacky" feeling that an InvisibleShield has is nice, but not as a screen protector. IF you keep your screen clean, the tackiness of the 'Shield makes it difficult to touch and drag, etc.