Sorry Bill... not true. Most of us listen to music through the internet. Streaming audio sounds just fine. IF... it is recorded and encoded well.
Most of us have our entire iTunes collection encoded at bitrates not much better than a decent web demo. Sure, use a smartphone's built in mic in a noisy NAMM hall, and it's going to sound like dog doo. But record to MP3 direct from the jacks, and you have the same audio quality as a decent rip of your favorite Reginald Dixon CD!
All my computer audio gets routed through my Mackie reference nearfields, so the speaker isn't an issue. And, I can assure you, a decently recorded MP3 of a G70 sounds EXACTLY like the G70 that is hooked up directly to those speakers.
No, I wouldn't buy an arranger without playing it first. But it has nothing to do with the audio. It is about where the buttons are, how the keybed feels, how easy is the display to see, stuff like that.
Sorry, but seeing a Wersi in person, after listening to high quality recordings of it, is not going to make me change my opinion one iota!
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An arranger is just a tool. What matters is what you build with it..!