Why does OS X format MS-DOS filesystems so much faster than Windows does?
The format process can be handled differently depending on what the OS actually accomplish by during the format.

Formatting should leave a clean and cleared file system. This can be done very fast by only clearing the file allocation table (FAT). This means writing to a very limited blocks /sectors on the disk.

Alternatively formatting may include clearing all the data previously on the disk/drive. This obviously involves writing to ALL of the disk and is a lot more time consuming.

Windows have the "fast" option and Mac OS X also has the "slow" option - OS X even has options to multi-wipe data with random garbage data (this usually takes forever).