My My Book (Essential Edition) came in FAT32 and remains that way. Recently, while posting on another thread I found out that it's recommended to format to NTFS deep down inside the directions (but I don't read the directions - so I didn't notice it).
The only issues are security and the FAT32 file size limit.
1) Security - I don't keep anything on it that's worth stealing!

2) FAT32 file size limit (~4 gB) - the only large files that I store on it are Acronis True Image images - and they're automatically split by the program, so I don't worry about it.