The Nexus 1 from Google is one of the few mobile devices with a stock build of Android.
It is the exception to an unfortunate rule where manufacturers are skinning Android with their own UI components at the expense of users.
Most of these interfaces are a personal matter of choice whether the user likes them or finds that they actually increase the usability or utility of their handset.
One thing that is not arguable however is that the Manufacturers who choose to do this are effectively becoming gatekeepers for Android updates to these Users. Need to Update to Androis 2.2? You will have to wait until you manufacturer has updated their skin and chosen to push the update to the User’s phone. The time for this is not exactly days and can be months, or never.
This differentiates mobile from desktop and notebook, where manufacturers could add some bloatware to Windows, but it could be removed and essentially made stock. This option is not available in the Android situation, unfortunately.
Manufacturers ideally should either make the turnaround times for updating phones much tighter (the update delay from from Android 2.1 to 2.2 is infuriating), or make their skin not stand in the way of defaulting to a stock install, or for that matter a whole market of 3rd party skins. If the User chooses to keep it, great, then the Manufacturer has actually made a piece of software front-end that enhances the stock UI. From recent reports this is often not the case, but because bypassing the custom UI is either prohibited or difficult, the Manufacturers are simply letting Google do the heavy lifting while they simply stand in the way of what android does best – promote rapid innovation.
Competition through exclusion of alternatives has never benefited customers.