Developer Preview 3 of Android O has now been released by Google. This is the third developer preview to come through with five expected to be released in total. This one follows on from the second developer preview which was only released midway through last month (during Google I/O 2017), along with the confirmation that the Android O Beta Program had officially started. So it does seem as though Google is now starting to speed up the delivery process of each preview.
With the Beta Program now in full swing, there are two ways in which you can apply this latest update. The first is to sign up to the Beta Program and once done, the next developer preview will roll out to your device as a normal OTA update, requiring the user to simply download and install the update as normal. The other option is to download the factory images and manually flash them over to the device. While the second option (the factory images) is the quickest way (as the images are available right now), the Beta Program route certainly is an easier way. Although you will have to wait a little while for the update to arrive organically.
As for the Developer Preview 3, Google has confirmed that this version includes final APIs for developers. Which although not necessarily something that will benefit the end user right now, is a major stepping stone in the Android O release schedule. As is the case with any pre-release preview, there are likely to be some aspects which do not work as intended, and Google has made a note of few of those 'known issues.' These include issues with the general performance and battery life, and issues which can result in the camera being slow to launch, as well as occasional audio stuttering issues when connected over Bluetooth. In addition, there are some issues with multi-window, issues with the Dialer, Gmail, and Messages apps crashing under certain circumstances. There also seems to be an issue specific to Pixel devices, where select homescreen UI elements have problems rendering. With this being a developer preview, it is only available to a select number of devices, such as the Google Pixel, the Pixel XL, The Pixel C, the Nexus 6P, the Nexus 5X, and the Nexus Player. As noted, factory images are now available and can be directly downloaded through the link below. Alternatively, head through the other link to join the Android O Beta Program and receive the update as an OTA.