I've been running them on my Pre and it made no impact on the ability to type or click on items on screen. With a phone like this and having a constantly exposed screen and no physical method of input, I think it's a sound investment. I don't want to take any chances damaging the phone.
I've got the zagg shield on my Evo. my only complaint is that its got an orange peel type surface effect to it.
That case you posted from best buy, looks way more similar to the seidioonline case than I expected. I was getting ready to order one from seidio soon, but I may look at the Best Buy one again . . .