"The unlocked device will run on both AT&T and T-Mobile in the United States with support for high-speed LTE data on both networks. This 'Nexus user experience' version will contain 32GB of built-in storage. Much like the special edition Samsung Galaxy S4 unveiled during I/O, Google will be directly handling future software updates," reports The Verge.
The Google Play version of HTC One will run stock Android, but it will have the same hardware like a regular HTC One. For example, it will have an infrared blaster that can't be used by Google's software because the stock Android 4.2 doesn't support IR. It's likely that a future Android update will add native support for infrared sensors.
I've mentioned in the post about Galaxy S4 that the Nexus Edition is great for Google, phone manufacturers, developers and users. Even if you don't buy this phone, you'll be able to install Google's software or a custom ROM that uses it.
Why use the stock Android instead of HTC's Android flavour or Samsung's Android flavour? It doesn't include so much bloatware, it's faster and easier to update. You'll miss features like HTC's Zoe or Samsung's Smart Pause, but you'll get a phone that's more responsive, has a modern interface and can take advantage of the latest software updates. Still, Nexus Edition phones aren't Nexus phones, so don't expect the same experience. The software wasn't designed with this hardware in mind.
Maybe the 'Nexus user experience' project has a different goal: show the difference between the pure Android and custom Android, running on the same devices. Maybe this will convince users that the stock Android is better and phone manufacturers will have to use it or at least provide an option to switch to it. As the stock Android improves, it's time to use it and build upon it, instead of hiding it behind useless features.