This response will not fully answer your question, but I can recommend a screen cover.
I have tried a variety of different screen shields and the Zagg invisibleSHIELD is by far my preference. It nicely hides fingerprints and cuts down on reflectivity (less glossy "wet" look) which is more to my taste as I do not like distracting reflections in TVs, monitors, etc. Moving my finger over the cover is fairly smooth with some very minor tactile resistance. However moving my finger upward does tend to stutter if I apply anything more than light contact.
Zagg offers an optional body cover, but it was not something I was concerned about for my particular needs. Given the sort of body armor you are reviewing, you might also consider a hybrid approach, e.g. the Zagg screen with some other body armor.
It is pricier than all the rest, but worth it, IMHO. If you go the Zagg route you can usually find coupon codes using your favorite search engine, like free shipping and save a few $$$. Every so often they email me ads; I just checked and the only thing I see is free shipping on orders over $29.98, but they are offering 75% off for select older handsets.
Also, I found the wisdom of this Youtube video http://www.youtube.com/watch?v=yZ4EM7EuT7U to be extremely helpful -- especially about wetting the shield on both sides and keeping you fingers real wet.
I don't have any vested interest in Zagg although I wish I could have gotten some sort of reward for the number of folks that are now using it thanks to my recommendation.
Hope this helps ...