No problems whatsoever on my 2015 Matte Silver F6B. This is the first vehicle I've owned with matte paint, and it does take some getting used to not having to wax...
I think the only possible issues I may face are due to hard-water spotting on the gray paint. I wash my bikes frequently using car wash soap and lots of water, followed by diligent (but gentle) towel drying. I've only had my bike for a short time, but I really like the classy 2-tone charcoal gray/lighter gray look, and will do everything I can to keep it looking new for a long time.