PianoMonk I was just comparing Roland GO:Piano to CT-S1, and I didn't think very much about other Casiotones than the CT-S1. My only information was forums-content, YouTube clips, spec sheets and availabe transport bag sizes and their pricetags. After the Casio won over Roland, I had a short look to the other Casiotones and thougt, CT-S1 is the most minimalistic one: no display, only few sounds, and I like the look with the fabric on top. This is where I get the most piano-like experience for my money. And I thought it is the slimmest one with lowest weight. Ok, on last point I was wrong.
Jeremy See claims, CT-S1 has better piano sound over CT-400. And JPS did play them side by side. Not Jazz, but still, listen by yourself:
After using it for some time when I am at my parents place my conclusion:
Would I buy it again? yes.
Would I buy another one instead with my today's information? no.
Are 61 keys enough? Often yes, sometimes not.
Would I go for 73/76 key now? No, not worth the added bulkyness.
Is there a feature I am missing? Yes, a small display to see the bpm of the metronome. That's it, basically.