To answer your question the case can work with a screen shield. However, it has to be really thin and not of the glass variety (think film). The edge of the case covers a small portion of the glass so you have to make sure your shield is centered on it or go with a "case friendly" protector that are cut smaller.
Aside from that the case is great. I've had one for each model starting with the 3G and all of them keep the phone looking new.