Elasty HD is a bit of software that's hard to categorize. It does common tasks like flip and retime but it has some advanced tracking and stabilization effects that don't look too bad in their sample gallery, although I wish the clips were longer. It feels a bit like a filter set that's run as a separate application.
It's odd that they're charging $39.95 for a beta version with the final version's price set at $59.95. For quick effects or as an additional option to things like Motion and After Effects it could be handy but I'm not sure.
The GUI reminds me of Pixelmator a bit which is a good thing. I'm keeping my eye on Elasty HD but I'm not ready to hand over any money just yet.
You can check out some screencasts of the app in use here.