Few weeks ago I tried Yamaha PSR295 at my local music shop. The sound quality wasn't very good via its own speakers. It's a very simple machine, not so many options/settings to chance, just selecting the style or playing without accompaniment. Those styles were not very good, neither the fills but at least you can identify drums as drums.

But you can't expect very much from that cheap keyboard though Casio CTK900, if it really has about the same sound quality that was on WK3500, Casio is way better. When I tried the WK I didn't try the styles at all, I only listened to the sounds and they were absolutely very good.

If I was you I would go for Casio or try to spend some more or/and try to find for example a used PA50 or PSR1500 or maybe WK3200/3700 if you can't afford them new.

Thanks Hasko,
I'll have to sleep it over... Now it seems that Casio would be my favourite.