You get the benefit of having multiple possibly giant workspaces. Imagine you're on a plane, you get the benefit of a 30" or cinema size monitor that you can look around without being limited to a tiny workspace.

It is a flat desktop because that is the most reasonable and quickest way to get up and running productively. I can scale it up and let users work as usual without inventing a new way for them to interact with their windows. Also, X windows and OSX don't give us the full tree of Windows so we can't accurately associate popups for example with their parent, so you'd have to have new windows and popups show up somewhere else. I did initially render the windows individually, so it is doable, but we'd still need a means of isolating input to each window, it's a definite possibility for Linux, and a weak one for OSX and Windows unless better support from the OS is released.

True, but Ibex also supports Quake3 levels on Linux and Ogre3D levels exported from Blender 3D on Linux so it doesn't seem that much more impressive visually honestly (eg: http://hwahba.com/ibex/files/page5-ibex-irrlicht-quake3-movement-done.png). The Wayland compositor is more impressive due to the Wayland support on the backend that lets one individually separate windows and manage them separately as a group, something that can only be done as a hack on Linux and OSX (possibly Windows, not sure yet). I'll add Wayland support to Ibex once it has proper 3D acceleration on non-Intel hardware, otherwise it would be a tad slow for most users. The Linux client lets you run full 3D programs like Blender and videos in realtime and that would be an issue without 3D accelerated surfaces from the underlying windowing system.

Honestly, I don't have a good answer as to how well this will work in practice. I think we'll need much higher resolution VR glasses for this to be of any use, but I'm keeping my fingers crossed that it will be slightly useable with the first iteration. This is more of a proof-of-concept in that it lets us even try out a virtual desktop and see what it looks like on consumer hardware, who knows what systems if any exist for research or military headsets? certainly not Linux and OSX. If this is found to be useful it should be trivial to add the right kinds of anti-aliasing and economies of scale should help bring high enough resolution displays to the market.

For your second point, you're right, it would get exhausting moving one's head around all the time to switch desktops. There is a keyboard interface so you can switch desktops (currently only supports one, but you can walk around with this interface as well), an iPhone client that will be updated to act as a remote control for motion and probably have gestures to switch workspaces, and lastly, the Leap Motion (http://leapmotion.com), highly recommend you check it out. The leap will basically be a tiny kinect for your laptop, the plan is to integrate hand gestures with that for motion and app switching, etc... that's the main goal as of right now.

I've looked at Open Croquet as well, but it is much more complex than what I need and isn't as cross-platform. One of the cool Open Croquet features is remote desktop sharing for example, I'm actually going for compositing your local desktop for as much speed as possible.

Also, if you check out the pictures and descriptions on http://hwahba.com/ibex you'll notice that it supports 2 3D engines in addition to the simple one from the screenshot: Irrlicht and Ogore3D which means you will be able to load up more complex worlds (Quake 3 levels and levels made in Blender 3D) and walk around them. I haven't gotten around to posting videos of those nor have I gotten around to porting them from Linux to the Mac yet. In time though once more work is done and a plugin system is completed.

Step one is to get a virtual environment that works, this works. Step two is to get a virtual reality headset, the Oculus will help with that. Step three is to write whatever programs you want that fit into that world rather than have every single VR program be its own separate entity requiring one to leave the experience just to even switch to another app. It is important that there be a beginning.

On Linux it is actually a compositor. On the Mac you use the built-in compositor to render the desktop to a virtual desktop then allow full interaction with it from the virtual world.

It also adds the ability to work with the Oculus Rift (http://oculusvr.com) so that you actually look around and the companion iPhone app (and as it is open-source any other platform really) will let you navigate. The plan is also to add support for the Leap Motion (https://leapmotion.com) so that you can navigate the world using gestures, look around anywhere you want, and if you want, still get work done.

Imagine you are on a plane, instead of using your puny laptop screen you can use a giant virtual one (or many giant virtual ones). This is just the beginning.