Starise
Thanks Jeff for that information. I've been connecting with the various user groups here and there. Seems to be a nice following for the PX-5S.
 
Here are my first impressions of the PX-5S so far. 
A very full featured stage keyboard. The sounds leave very little to be desired in terms of quality. I ran across a slight warbling sound in the concert grand sound at times.This could have been my mod wheel being slightly up. I'm still not sure because the wheel seemed to be down when I moved it. The problem went away when I changed programs and came back to it.
 
The keys action is perfect for a trained pianist, although if you plan to record keys and vocals at the same time the action noise would likely be picked up in your mic. Since this is one of my preferred methods to record, I might need to do my takes seperate from now on. FWIW my last keyboard wasn't much better. They all seem to have some noise.
 
I group the keyboard into three main sections. The main sounds section, the synth section and the arpeggio section.
 
The synth section is pretty deep, especially for a board in this price bracket. The fact that using the hex feature allows for multiple layering of sounds in different zones allows for a lot of creativity. Add to this the arpeggio section and you have a lot of capability. The built in arpeggios are  good. The adaptable sliders and knobs are mapped really well in the factory settings. You can for instance, change resonance of a thick synth sound on the fly.
 
Now here's some of the things that I liked less about the keyboard. The company has put a lot of capability behind a user interface that can be confusing, especially if you want to get deep into the synth, layering and zones. I realize that concessions had to be made and they were made in the user interface. I've used a lot of keyboards, so I thought that I wouldn't have any problems in using the basic functions. I was wrong. I needed to look at the manual to find how to change basic sounds. I dare say many of the people who would buy this probably won't ever use many of the deeper features for this reason. Once I was onto the scheme of it though sound changes were easy.
 
Many of these limitations can be worked around by simply reading the manual. My manual left out the sound preset numbers and only by going online could I find them. To be honest I haven't yet located or used the software program that makes internal adjustments easier. This should make getting deeper into the program much easier.
 
This is a nice keyboard, especially for the price. Makes a decent midi controller. Once past the learning curve you can take full advantage of the capabilities. The learning curve might be frustrating if, for instance, you're trying to set up a totally new multi zone synth from scratch.
Once done though, the rest get easier.
 
Considering that in the beginning I mainly wanted a midi controller with some nice internal sounds in it, this goes way past that. Anyone who wants a midi controller with some extra kick can't go wrong here IMHO>
 
 

Jeff Evans
I am thinking of putting a Tangerine Dream type live band together playing original electronic music and the Casio would make an excellent live controller for me I think as well as one or two other light action keyboards.