GNOME Twitch is a GNOME 3 application for watching Twitch.tv (a popular live streaming video platform that primarily focuses on video gaming) on your desktop, without Flash or a web browser.
The application lets you browse the games and channels, search, add favourite channels, set a default video quality, change the quality per stream and the volume.
Unfortunately, GNOME Twitch doesn't support logging in to your Twitch.tv account, which means there are no notifications (but you can use Twitch Indicator for that) or any other features related using your Twitch.tv account. Comments are also not supported (both viewing and posting comments) right now.
However, considering that the application is only a month old, I'd say that it's already pretty good and it has already replaced the Twitch website for me.
Why use GNOME Twitch? The short answer is: because, unlike the Twitch.tv website, it doesn't use Flash - and this should be enough to answer the question.
Here's the long answer though: while Twitch.tv now uses HTML5 for the video controls, it still uses Flash for the video itself, which makes it very resource-heavy.
For instance, watching Twitch in Firefox (fullscreen, source quality, Flash 11.2), the Flash CPU usage was about 140-150% in my test (with some extra CPU usage for Firefox itself), while using GNOME Twitch (with "gstreamer1.0-vaapi" installed, tested under Ubuntu 15.10), the CPU usage (fullscreen, source quality) was about 10-12% in my test.
Why use GNOME Twitch? The short answer is: because, unlike the Twitch.tv website, it doesn't use Flash - and this should be enough to answer the question.
Here's the long answer though: while Twitch.tv now uses HTML5 for the video controls, it still uses Flash for the video itself, which makes it very resource-heavy.
For instance, watching Twitch in Firefox (fullscreen, source quality, Flash 11.2), the Flash CPU usage was about 140-150% in my test (with some extra CPU usage for Firefox itself), while using GNOME Twitch (with "gstreamer1.0-vaapi" installed, tested under Ubuntu 15.10), the CPU usage (fullscreen, source quality) was about 10-12% in my test.
Without the "gstreamer1.0-vaapi" package, the CPU usage was around 60-70% which is still a lot better than Flash.
I should also mention that the application uses header bars, which means it doesn't look that pretty under Ubuntu 15.04 and other desktop environments that don't fully support header bar apps.
Install GNOME Twitch in Ubuntu 15.04 or 15.10
To install GNOME Twitch in Ubuntu 15.04, you can add the GetDeb repository by installing THIS deb and then simply install the "gnome-twitch" package. The GetDeb repository doesn't yet support Ubuntu 15.10 however, you can use the 15.04 deb and it will work in 15.10 (link below).
For both Ubuntu 15.10 and 15.04, you download the GNOME Twitch deb from HERE.
Unfortunately Ubuntu versions older than 15.04 are not supported.
Arch Linux users can install GNOME Twitch via AUR.
app seen @ lffl.org