The onboard filters are pretty close to an MS-20, though their response feels a little less smooth or “creamy”. Still, it is very very close to that original sound.
It also has the same problem as the Korg MS-20 mini when it comes to MIDI. If you are sequencing it via MIDI you need to make sure to not tie any notes together otherwise the synth will play them legato, without retriggering the envelope.
My filter knob started to sound very noisy after one year whenever I swept the filter, turns out that the potentiometer was pretty bad and had to be replaced.
Overall a good deal for your money, you get that legendary ms-20 sound for a cheap price, just know that it might have some build quality issues (your mileage may vary)