Have you tried Goodvibes? It's a new lightweight internet radio player.
https://github.com/elboulangero/goodvibes

Personally I use Gradio, but for you it can be not as "lightweight" as you want. You can also listen to internet radio stations with Rhythmbox.

edit:
You can't add the stations with GUI on Radiotray-NG, you have to manually edit a JSON file. I don't know if it's suitable for the target users of Solus.

@Shrug Thanks for the suggestions. Gradio is quite powerful but its default application window is so big that it doesn't fit on my screen. Rhythmbox is more a universal music player, less a dedicated internet radio. Both don't look and feel as good as the minimalist radio tray. I didn't know about Goodvibes and installed it just now via the .deb file in Ubuntu. It is not as feature-rich, still in early development and doesn't have the elegant system tray design of radio tray.

You can't add the stations with GUI on Radiotray-NG, you have to manually edit a JSON file. I don't know if it's suitable for the target users of Solus.

The previous radio tray I have used had a fair amount of radio stations available and I never had to manually add any stations. Judging from the latest screenshots there are plenty of them. In any case, the maintainer has indicated that a cross platform editor application is on the roadmap. Regarding its ease of use: I find radio tray way more intuitive to use than either Gradio or Rhythmbox and would recommend it especially for beginners.

@baimafeima If this is packaged, it won't work in Budgie (it uses AppIndicator), but it will work in MATE. If that's fine with you, I will accept this.

If this is packaged, it won't work in Budgie (it uses AppIndicator)

What would be required to make it more distro-agnostic and to get it to work in Budgie as well? If you provide me with detailed information, I will forward this to the developer. In any case, I am using both the MATE and Budgie editions and I think it would be valuable for many MATE users.

Great, thanks a lot for checking back.

Will try to build it today :)

Checking for one of the modules 'ncurses'
CMake Error at /usr/share/cmake-3.6/Modules/FindPkgConfig.cmake:646 (message):
  None of the required 'ncurses' found

Do not manage to find how to include ncurses, both tried with ncurses and ncurses-devel as builddeps bu it does not work

@BridouZ did you use pkgconfig(ncursesw) instead of ncurses-devel? That might be your problem

Neither are needed, ncurses-devel is in system.devel.

Oh yea. Is system.base the other component that is always installed?

Yes, it's the base of the system.

Also here is the relevant ncurses error line I believe: pkg_search_module(NCURSES REQUIRED ncurses)

should be looking for ncursesw, not ncurses:

$ pkg-config --print-variables ncursesw

exec_prefix
includedir
libdir
major_version
pcfiledir
prefix
version

I'll try to get this one packaged as well.

@JoshStrobl Thanks for your feedback. I have raised these issues upstream (https://github.com/ebruck/radiotray-ng/issues/9) and a new version addressing these issues has just been released: https://github.com/ebruck/radiotray-ng/archive/v0.1.5.tar.gz

Change log:

• Fixed startup crash seen on some systems using gcc 6.x
• Added compact-menu option to disable the use of menu separators
• Removed ncurses requirement if appindicator library is found
• Notification uses station name if artist tag is missing
• Smarter boost dependency detection
• Added rt2rtng script for converting RadioTray bookmarks
• Fixed user-agent and release build issues
• Logging & aboutbox now include git commit used to generate binary
• Added optional mapping of media keys for previous/next station etc

Will evaluate today. Thanks for filing the upstream issue baima =)