The Casio sounds interesting and what is good about it is the price. It is more affordable. A Kurzweil for example is quite a bit more expensive but then again it is actually way more powerful and the sound quality probably still up there as one of the best.
I can't seem to find any link between Casio and Ray Kurzweil so that information may be incorrect. I can’t see why Ray would actually ever need to design someone else's instrument. But if he did have anything to do with it then that explains why it sounds so good. But I am sure Casio are quite capable of making a good sounding instrument themselves.
I like the stage piano concept of the Casio with a powerful synth built in. It seems like a good idea to me. I have come across Casio in my teaching sound production in colleges capacity and every time I have been impressed with how they sound.
Where I am working now for example they have just invested in a new Yamaha PF115 but it is nowhere as interesting or as powerful as the Casio PX5S. The Casio is even a great price in Australia too.
Sorry to hear
backwoods was having trouble with his Kurzweil. I have had many and never had any issues such as his. The display on mine is large, very sharp and very high contrast as well. The PC3K6 is a much lighter 61 note synth action model and it much easier to move around. I think the balance of weight of the instrument overall and a weighted action is important. Sounds like Casio might have it right for example.
Crud is a poor choice of words to describe Kurzweils. They sound incredible and sound wise have been out front way earlier than anyone else and been there for a long time. Yes other brands have only caught up in sound quality but Kurzweil set the bar a long time ago and have kept others pushing their sound quality forward for years to the point where they are now. Features are important but sound is also very important. A slightly thin sounding instrument will fall down live and in the studio.
I used to play in a band with a great keyboard player who bought one of those Ensoniq TS10's and used it live with a nice Bose system. But it sounded terrible. He ended up with a Roland that just sounded way better live. The sound had more depth and power and worked against the live drums and everything else much more so. I have recently stopped playing with an Elvis and Orbison tribute show and that keyboard player had a Yamaha SY85 and I did not like it live either. It struggled to sound fat. Later he got a Korg stage piano and a Roland Fantom and then everything suddenly got way better.
These cases were a real eye opener for me in how poor some of these things can sound live. Against my massive Sonor drum sound, a big bass rig and guitar amps etc.. Only decent instruments can hold their own in these types of situations. The keyboard stage sound system is also another topic too. It needs to be good and I mean good.