Unfortunately, Ubuntu for Android is not yet an open project, and is only available to manufacturers interested in integrating it into their products, as in the case of Motorola with Atrix. Because installation is complicated and also depends on hardware support, it is likely that it will never be directly available for download from end users, as is the case with regular versions of Ubuntu. However, whether Canonical or not, system images will eventually eventually leak and be integrated into alternative ROMs, as in the case of Cyanogenmod, thus reaching more users.
Hardware requirements are relatively modest, including a dual-core SoC ARM of at least 1 GHz, video acceleration, 2 GB of system image storage, HDMI output, USB host mode support and 512 MB RAM (though 1 GB are recommended).
For manufacturers, Ubuntu for Android is a tempting proposition as it costs little to integrate (the manufacturer only needs to make sure to include at least 1 GB of memory to run both systems comfortably as well as the required interfaces) and they You can still earn a few bucks selling the dock and accessories, as well as benefit from the additional advertising and sales. Should several manufacturers adopt the system, Canonical has a chance to have a ripple effect, prompting all major manufacturers to integrate the system into their high-end models.
If we compare this strategy with Microsoft's, for example, we see how Canonical came up with a fiendishly brilliant idea to grow in the mobile market, hitching a ride on Android's popularity rather than trying its luck trying to force adoption of a new system.
The main question regarding the real market for using the phone as a desktop. Although this is a cool feature, which most will want (although it does not increase the price of the handsets, of course), there is no doubt about how many will actually use the function in practice. While today's ARM SoCs offer very competitive performance over dual-core Atom, they still deliver performance in the netbook class. Anyone who has a sturdier desktop or notebook certainly won't want to swap it for a phone that can open just a few simultaneous browser tabs before it starts to choke.
On the other hand, the fall of the Flash plug-in brought down one of the barriers to entry to the platform, as Flash has never been worthy of running on the ARM platform, unlike HTML5. Integration with Android and its applications is also an important advantage, as it allows you to continue working with the same data and jobs to be docked ie with the phone in hand, which sounds far more interesting than carrying a netbook under arm. The combination is unlikely to threaten desktops, but it is likely to contribute to a few percentage points lower share of netbooks as laptop-docks like Atrix become more common and more accessible.