I heard there was some differences with the two cfws, as for govanify's I heard it allows you to run a firmware spoofed JPN Flipnote Studio CIA (Requires Firmware 5.1) while Palantines apparently can't. Which CFW is better?
I really don't like the term "custom firmware", but I guess people will not change their habit now they are used to tell "CFW".
It's only a redirected NAND, not a patched firmware flashed back to the console.
I wish we could stop using this word and start using proper terms.
As for the differences :
Govanify version has a "call home" function, your 3DS connects to his servers and he sees how many console are using his patched NAND, he can get your IP and maybe other data if your 3DS is sending private info.
Palentine only removed the server's access.