Firstly, this is really impressive and a great idea. Thanks for starting this project, as Linux badly needs some new ideas for UI design. I've had a look at the video.

Unfortunately, my first impression from the video was that this is a direct copy of OS X, down to the apps, and in terms of UI and experience, not in terms of skin-deep chrome. The reasons for that were:

General window chrome - toolbars, buttons

Dock on bottom (why not sides, our screens typically have too much horizontal real-estate?), bouncing icons in dock, similar 3D shelf feel to earlier Mac OS dock.

iTunes app demonstrated has a UI which is almost exactly like the iTunes in Mac OS - there's plenty of room for innovation here, why present things in the same way?

Finder app again presents exactly like Finder in Mac OS, but with tabs

System preferences again has a layout very reminiscent of Mac OS - in isolation this doesn't mean much, it's cumulative

Exploded windows view is very like Mission control, X symbols on top left look like iOS

Spinning progress indicator is similar to the style introduced by Mac OS

Typography is reminiscent of iOS7 because of use of Raleway which is reminiscent of Helvetica Neue - not a big deal and it is a nice font.

Window chrome is a close match to the current Mac OS grey, fullscreen buttons top right, titles centred etc. Again, in isolation this means nothing.

So those are some reasons people might think you are copying from Mac OS X - NB the grey window chrome is the least of your problems. Individually they don't mean much, but cumulatively they give the impression you haven't spent enough time rethinking the way these apps and OS services work and have by default chosen the Mac OS way - I think if you want to call it an OS (built on Linux) it should provide a different experience, which is different enough to be new and interesting. One other tip on your video was that to me it feels like you're rehashing the discussions you had in making a video for the first 20 seconds - I don't care about all that meta stuff, I just want to see the OS in action. Just jump in with something impressive.

So all that negativity out of the way (and I thought it necessary because you don't acknowledge that you did intend it to be reminiscent of OS X), this is a great effort, and I might even try it out sometime (like most people I have a very high resistance to switching OS, but this one is intriguing). You have clearly put a lot of work and polish into this, so congratulations on the effort, and I think it's a really worthwhile project, but be wary of sticking too close to existing designs.

Mac OS X is not the apotheosis of interface design, far from it, it's just one of a million possible pathways, and is probably at a local maximum where you can't easily escape without trying things which are radically different.

Personally I'd put some effort into differentiating yourself visually from other OS's, not just for the sake of it, but because there are so many other possibilities to explore - there are tons of areas you could improve - launchers, overlapping windows, window chrome (do we need toolbars there all the time), as that's an important part of the first impression, and if you have something sufficiently different it can really help people remember you and be tempted to try it out. Think for example of the tabbed windows in BeOS, it immediately gives it a different identity and makes it stand out, without sacrificing usability.