The Android M, or Android 6.0 Marshmallow, update has already been available to select users in South Korea and the U.K., thanks to Samsung's beta testing the upgraded operating system on some Samsung Galaxy S6 and Galaxy S6 Edge devices. And when Marshmallow begins rolling out to users in the U.S., you can expect some features of the user interface to be eye-catchingly updated.

That's according to screenshots from the upcoming Android M update for the Samsung Galaxy S6 and Galaxy S6 Edge that have been posted recently by Samsung-centric news blog, SamMobile (via IBTimes).

The shots come from a beta test conducted by Samsung in late December 2015, a beta that is no longer open for new participants, unfortunately. Nevertheless, they reveal a lot about how the new Android 6.0 Marshmallow update will look with Samsung's new TouchWiz UI layered on top, and the results are quite pleasant -- especially if you're a fan of Apple's iOS 7 and onward.

The Android Marshmallow 6.0 beta on the Samsung Galaxy S6 and Galaxy S6 Edge features a new light blue color palate for Quick Toggles, for example, while the Status bar is now white.

But the biggest change is the lack of depth throughout the redesigned TouchWiz interface: the power menu, icons, and other aspects of the interface that used to have skeumorphic textures and depth are now notably flattened.

Add in the background softening effects of the App Drawer and other menus along with the current standard Galaxy S6 wallpaper, and you'd be forgiven for thinking the Android 6.0 Marshmallow update running on a Samsung device was iOS 7 running on an iPhone, circa 2014. That's not to detract from the attractiveness of the updated interface, Android diehards.

While it's surprising that Samsung waited until a year after Android 5.0 Lollipop brought a major UI redesign to millions of smartphones, with its concept of Material Design, to overhaul its own UI, the change will likely be well received by Samsung Galaxy S6 and Galaxy S6 Edge owners.

Perhaps the big TouchWiz redesign also explains why Samsung Galaxy S6, Galaxy S6 Edge, Galaxy Note 5, and Galaxy S6 Edge Plus owners here are still waiting for the otherwise small, iterative Android 6.0 Marshmallow to get an official OTA rollout update release date from Samsung in the U.S.