The only real catch seems to be that videos appear under the "Gallery" tab rather than the "Video" tab, which is reserved for content purchased on the Kindle Fire itself. Otherwise, this looks like a simultaneously simple and versatile solution for encoding video, and it also functions well as an alternative to iTunes for playing and managing your media. Kindle Fire users aren't the only ones who might be interested — Miro supports iOS, Android, and the Sony PSP as well.