Many PC card readers are only good to 2GB, then 32GB and beyond that it gets to be a support headache.
http://www.tomshardware.com/answers/id-1726154/format-64gb-card-exfat-fat32.html notes the other big issue.
I have a 64GB microSD. I try to transfer folders from my PC to the SD card, and it does. However, when I open a folder, there are no files inside. I formatted my sd card to fat32.