Most international non-carrier HTC One phones have already got Android 4.3 and despite OpenGL 3.0, Bluetooth low energy support and a few minor tweaks, there is nothing special about this release.
Android 4.4 will bring a few minor changes and the most prominent option is that you will be able to use an alternative SMS application instead of the default one. Of course, some other minor tweaks are coming, too.
Our contacts have told us that company wants to focus on other internal projects and improve its Sense software rather than put a priority on implementation of Android 4.4. HTC One Max and HTC One won't be getting Android 4.4 this year and they can expect update at some point in early 2014.
It takes a long time to test these new builds and it costs a lot of time and resources and therefore it is not something that HTC wants to push right now. HTC has developed the rather unique Sense 5.0 and 5.5 UI that many HTC users love and the company will continue to improve its own overlay on top of Android software.
Let me remind you that HTC Remote and Car mode are definitely something that you miss when you change the phone, as the remote works well and the car mode makes it easier to use the phone while driving.
Of course Samsung and LG do have their own alternatives, but a lot of HTC users have been using Sense since the legendary HTC HD2 and the early days of Windows on HTC touch-enabled phones.