Good evening Yves,
Just to give my opinion, Ok, 400€ even revised is an unaffordable sum for a Solton keyboard that is more than 20 years old, whose contacts are more than likely oxidized (springs) without counting other anomalies or hidden screws.
No, I would not buy it.
From the point of view of rhythms it is basic compared to what came out in the following models from Solton (Models SD. XD etcc...)
Sometimes on 2nd hand there are good opportunities in button keyboard.
Ask my friend Louiguy who is a member of our community here on P-A, he knows a lot about everything related to Solton/Ketron.
Have a nice evening.
Jodi