Amazing compression for HD? Has anyone else used this?

Recently a colleague and I stumbled across a technique for high quality compression that we have yet to find a downside for.

(Especially for HD output in After Effects) we use the following:
1. Quicktime
2. (under settings) use the ANIMATION setting and then set the quality slider down to about 65.

This gives us anywhere from 5 to 20 times smaller file sizes than uncompressed AVI or uncompressed .MOV, and it even results in incredibly small file sizes when using RGB+ALPHA. In fact, some of our alpha channeled footage was smaller than regular RGB only footage. This can be used even with the "Lossless with alpha" preset...just go under the settings and change to animation and use the quality slider.

We did some comparisons, by outputting and then placing the footage up against the original and scaling both up to 400% with no VISUAL loss of quality (I'm sure scopes would reveal some weakness, though)

This could be a real space saver for those of us dealing with the horrible burden of trying to archive large amounts of HD data.