Just updated to Win 8.1 RTM (technet subscriber). Seems that Decor8 does not fix the gawd awful mess that they did with the background color of the tiles. Will this be addressed in an upcoming release?
FYI - The tiles in Win8 would all be the same color and Decor8 would set that color based on the colors in your background image ( if you chose that option ). MS has made the tiles to now take on the predominant color of the icon itself now for some stupid ass reason....