Ultimately it comes down to personal preference. Only you know what is best for you.
Although I have used Linux for many years, I am new to using newsreader software so I can't recommend a particular newsreader.
I would say however that, generally speaking, I prefer using native apps rather than using Windows apps through Wine.
Also, for historical reasons, there are basically 2 camps on the Linux desktop - Gtk and Qt. You said you are using Xubuntu. Xubuntu uses the Xfce desktop which is written using a toolkit called Gtk. Therefore, apps written in Gtk tend to integrate better in the system. Qt apps (like KNode) will work but fit in better if you use the KDE desktop.
You will find Linux users tend to favour either Gtk or Qt apps. Again, this comes down to personal preference really.
Here is an article which compares some different Linux newsreaders. It is a bit old now, but hopefully might give you some idea of what is available.
If you're interested there is an article on Techradar called "Reviewed and rated: the best Linux newsreaders". It is 5 years old now but probably still worth a read.
They reviewed the following clients:
1) Gnus - this is what I am using but I would not recommend it for a non technical user as it is a command line (non-graphical) app and requires editing of config files to set up.
2) slrn - again this is a command line app.
3) Thunderbird
4) XPN - Gtk app
5) KNode - This is a KDE (Qt) app.
6) Pan - They rated this one as the best. It is a Gtk app.