i understand what you are saying - quite frustrating. i guess i wont get one, i like my fast typing!
The iSkin one is too thick. I use the Moshi clearguard, it is very thin and doesn't bother my typing one bit. The only thing you have to get used to is the slightly soft feeling it has around the edges when the keys are depressed. iSkin is made from silicone, the Moshi seems to be made of a thinner and less elastic material (harder plastic). Plus I believe it is cheaper than the iSkin, go figure. Don't waste your time with the cheap ones on eBay from China, they will stretch and be unusable in a matter of months.