MetroTube has been everyone's favourite YouTube client for Windows Phone for years - and it just got a bit slicker, with a whole new secondary UI for channel and category browsing, dubbed the "river" by its developers, shown off in the video below. This river of icons runs along side your video list pane and can be used as a control panel or expanded as needed - see the video for a better idea. The new UI pops into use when you tap on 'More' in any of the standard panorama panels. 

Thanks to WPCentral, there's a brief textual changelog:

• Main panorama facelift
• Sub navigation UI overhaul
• Long titles can now be viewed when clicked
• Full screen button (for phones with rotation lock on)
• Playback bug fixes
• Various bug fixes and improvements

The new 'river' secondary UI (handling all channels and category browsing) is quick and convenient:

It's also very Android-like, in the way the controls slide in from the side - the concept of the icons and thumbnails showing the first graphical element (or first few characters) of a channel or category, and then you swipe across to reveal the full name, works very well:

Slightly confusingly, there's no obvious way to tap on something to get back to the main 'home' UI, but it seems that the humble 'back' key works well here, so all's well.

You can buy or update MetroTube here in the Windows Phone Store. The best $1 or 79p you'll ever spend!