We tried a variety of screen casting methods to try to give feedback to students on their work. Each with benefits and downsides. Quicktime is good, but it requires saving on your computer, jing and screenr is limited to 5 minutes but saved online and you can provide the link to the students.

Here is a sample link of a screen cast feedback on a student science lab. I haven't watched it yet myself, but this was done in jing and then I posted the link for the student on Moodle.
http://screencast.com/t/XkdAOPZI