They should all be the same, right?

And besides, there isn't much you can do with jailbreaking. Kindles already support sideloading books, fonts and dictionaries, and the two links the other guy posted are all you really need to start pirating ebooks. The devices themselves are so weak that you really can't do anything other than read books on them. Kindles nowadays also support book cover screensavers, which was a big reason to jailbreak in the past (apparently). That should tell you about the kind of functionality jailbreaking gives you.

I will say that if you end up buying a Kindle, you should install the KFX plugins for Calibre, they're the proprietary format that Kindle store-bought ebooks come in. The Kobo equivalent is Kepub.

super metroid and metroid zero mission. Man I love those games.