I bought the Moshi screen protector along with the Marware leather case and had no problem getting it to fit. There's a lip around the outer edge of the Kindle Fire screen into which the frame of the screen protector fits quite nicely.
I must, however, disagree with the reviewers who gave this product high marks for outdoor viewing. I couldn't see the screen at all in the sunlight. If you're in the shade it's slightly better. But to recommend the screen protector for the purpose of outdoor viewing is misleading.