RAW essentially means no file system. You will not be able to write anything to it until it's formatted (unless you have special software that works with unformatted volumes directly).
I'd say go for NTFS, or FAT32 if your files are under 4 GB.
That's pretty much correct. I just wanted to add that we've implemented exFAT support in the latest version, which basically brings the best of both worlds:
Better performance due to the lack of journalling and optimised file system organisation; and
Very high limits on the number of files and their size, more than sufficient for modern usage.