The sound is good.

It produces a clean sound, and actually slots nicely.

The sound of the trumpet is excellent.

The sound of the instrument is not bright, like a normal C trumpet is expected to be.

Use a real, brass one, to get an actually decent sound

The tone sounds like a trumpet, but it is a very dead sound, no resonance to it

The effect is similar to a cup mute; dulling the sound, less volume, no ring, and makes it a bit airy.

Surprisingly good quality and sound

The trumpet actually has a good sound; it plays clear and no major intonation issues

Update: After playing it for a few days I do notice some intonation issues, like low D is really, really sharp.