What is the best free software for OS X Mountain Lion for enabling write support for FAT32 and NTFS?
As pointed out in the comments, there's no write restriction for FAT32 volumes in OS X.
Try NTFS-FREE, works for me on ML:
This program allows MacOSX to access Microsoft NTFS formatted harddrives connected by USB port. A modified version of the original Linux code, this program is packaged as a easy-to-use installer so that normal users can install it without hassle
Fuse4x + Ntfs-3g works on OS X Lion. All freeware.
In Terminal, type
brew install Fuse4x.
brew install ntfs-3g.
brew info fuse4x-kext. Enter the 2 lines of
$ sudocode separately at the start of the text given.
brew info ntfs-3g. Enter the 2 lines of code separately after the line "To replace the default Mac OSX automounter:" .
A restart may be prompted.
All the best.
As for me I use Paragon NTFS for Mac. Firstly, it is very fast, secondly, I can rely on it and I'm sure that it won't corrupt my files. Yes, it is commercial with 10-day trial but it is worth spending money. Moreover, it is cheaper than Tusera NTFS!