Why should we Linux developers come together and write an application that suits all the needs when we can scratch our own itches? :-) So, here is YAACA: https://github.com/chripell/yaaca . It is written in Python and C and I regularly use it with the ASI1600MC, ASI120MC and ASI120MM ATM. It tries to be both fast for planetary imaging (capturing is in C) and suitable for EAA (online stacking, dark subtracting, gamma stretching). You can find packages for Ubuntu LTS 12.04 and Arch Linux (I don't have other distros around unfortunately).
It is written in Python because I realize that I don't have a lot of time. Leveraging Numpy and Scipy makes everything nicely productive. But the saving path is in C because it needs to be as fast as possible to not lose frames. For the same reason saving is to .SER (I tested the output with AutoStakkert and WinJupos), I think AVI and such is just a thing from the early hacking on webcams, it is a really bad format for scientific imaging because it is almost always lossy. I may consider adding FITS but I don't see many uses cases either.
It would be pretty easy to support MacOSX but I don't know if it makes sense (or there are already good and supported programs like on Windows, I have no idea). I am much more interested about Android. Also I'm considering adding INDI support and various image processing, guiding or stacking (image processing is my actual hobby :-) ). Feel free to suggest features/changes or let me know about bugs if you happen to use it.