Editing compressed video

This card allows you to take the uncompressed HDMI signal from your camera (if it has an HDMI output) directly into your Mac. It does mean you'll have to have a Mac connected WHILE you're recording, otherwise the signal will be already compressed on disk or tape, which sort of defeats the whole purpose of the product.

The card may be most useful for indy filmmakers, who don't mind lugging a Mac (or PC) from set up to set up. In that realm, this card is a breakthrough product; hard disk configurations that were available for that purpose easily ran into the tens of thousands of dollars. Now you can build your own, at a much lower price.

Useful for consumer level video cameras, yes. Useful for consumer level videography (e.g. shooting your kids), not so much.

I have owned and used several Blackmagic products, and their high quality (and low price) are hard to beat.