At the recommendation of many members here at Nikonians, I picked up a GGS glass LCD cover. The optical glass seems better, to me at keeping grit out, it can get in there but being glass, it does not compress to "rub" the grit into the LCD screen. I picked up mine for my D700 on eBay rather inexpensively.
Mine kit had two pieces, one for the LCD the other for the top LCD. The top LCD cover has adhesive tape to secure it to the top panel. I used a Nerf gun suction dart (you can get by with a small suction cup) with a little water on the tip properly align the GGS cover on the LCD. Looks great. The LCD screen secures to the back of the camera the same way the Nikon plastic screen does, but is definitely more scratch resistant and easier to see in daylight. I recommend it.
Search GGS and you can find other happy users. (Note they are camera specific so be sure to get one for your specific camera if you decide to purchase one.)