If you're still on the fence about picking up a Google Play Edition of the LG G Pad 8.3, Sony Z Ultra, or HTC One M7, you may have run out of time. All three devices are presently showing as out of stock on the Google Play Store. History tells us that once devices go out of stock on the Play Store, they often tend to remain in that state indefinitely.
In addition to things like stock Android and being carrier-unlocked, one of the big features of Nexus and Google Play Edition devices that Android power users love is an easily unlockable bootloader. While OEMs and carriers often make a policy of locking their devices' bootloaders to prevent installation of unauthorized software, Google makes it very easy for us to tinker with devices bearing its brand. All you really need to unlock a Google device is a tool called "fastboot," which is made available through the Android SDK.
If you own an HTC One GPE, it's time to start keeping an eye on your system update screen. HTC has released kernel source and framework files for the new update and people are beginning to report receiving the actual update. The firmware version is 3.62.1700.1, which is Android 4.4.2/KOT49H. This brings the HTC One GPE up to date with current Nexus devices.
If you want to know what's changed between 4.4 and 4.4.2, check out our comparison.