Here's the comparison of the Flip vs Exilim Z80. Here Z80 didn't exactly win "across the board" (e.g. battery life), but it's pretty close.
I highlighted the winning points of Z80: higher video resolution, optical zoom, larger storage /longer recording time, and lower price.
Z80 is shorter but a little fatter. Overall it's about 8% bigger. But if size really doesn't matter for you, consider Exilim S10, it's only 0.59" thin and smaller than Mino overall.
I actually don't care much about image quality of Z80. I have a Rebel Xti. I bought Z80 specifically for it's video capability.
There's a red button for one-button video recording. One criticism of using digital camera for video capture is that you have to set to to movie mode. But with this red video button, the argument goes away. You just turn it on, push the red button, and you are recording, it's that easy. Takes 5 seconds? No, more like 1.5 second!
One nagging point of Z80 is that it output video in "mov" format (h.264 encoded). Yes, Quicktime format. I actually don't like it but it would have been great plus if it's judged by Michael Arrington. He said "everyone is moving to Quicktime at this point." Not me, I'd rather install "quicktime alternative" then to install Quicktime/itune.