There are different types and forms of microfiber and you need to be careful of what you purchase. We have seen some companies selling screen cleaning products whose microfiber offering was actually a microfiber used for clothing NOT intended for screen care.
The basics about microfiber are important to understand as you concern yourself with scratching.
The way a microfiber cleaning cloth works is that it picks the dirt and debris up off the surface and traps it in the fiber pattern in the cloth. Making it the ideal and preferred cleaning cloth for delicate surfaces. Unlike traditional wipes or paper towels that just push the dirt and debris across the surface and microfiber actually lifts it off the surface. However, what makes it such a great cleaning cloth can also make it a potential problem. What most people fail to realize is that the more you use a microfiber without cleaning it the more it accumulates dust and other debris. The cloth can only hold so much before it become over-taxed and a potential problem. What microfiber users need to know and remember is that it is best if the cloth is shaken out before each use or washed (by hand or delicate cycle) once every week or two.
Microfibers are the best solution for cleaning sensitive screens, but like anything it is good to know the proper way to use the product to get the most out of it.