DGX-530 / YPG-535 -- These two models are sort of like 88-key versions of the DGX-230 and YPG-235 in the sense that they were released at about the same time, but I think it has other improvements besides the greater number of keys. I don't think the keys are hammer action, but I think they have better action than those of the DGX-230 / YPG-235.
Hi, Michael - You mentioned the YPG-535; I already own a YPG-525, a very similar board. It has a dead display, which makes it virtually useless. However, I have a new display dog-paddling its way from China to Canada; I expect it will arrive in the next few months, and I'll install it. It might well be that the YPG-525 I've already got will fill all my needs. Except for the joy of having the heady aroma of freshly molded plastic in my home, of course. Perhaps I'll get one of those 'new car smell' car fresheners and hang it in my music room.
I also identified the PX-560, but the $1,500 price tag is a bit steep at the moment. However, I'd rather save for something very capable, than buy something that won't do the job. The 560 uses the Casio AiR sound engine, the same one they use on all their high end electronic pianos.
I've researched the heck out of the Casio WK-7600, and it seems that the strong suit of the 7600 is its drums, percussion, and punchy sounds. This makes it a good choice as a rock or stage performance keyboard, particularly considering its light weight. But its been criticized by a few sources as having good, but not great, classical instrument samples. I tend to do slow, moody compositions which feature individual instruments (sax, violin, piano) and very rarely have a rhythm background (although this may change, as I develop more as a musician). So, despite the fact that I absolutely love the technical capabilities of the WK-7600 - it does virtually everything except set the table and make breakfast - the sounds it produces don't seem to be the ones that fit my musical style.
Of course, Casio has just announced their AiX sound engine which they claim is a dramatic step forward in sound realism. It is currently available on the CT-X700 ($175 USD) and will be rolled out on three additional 61 key keyboards by late March. They claim its eight times more powerful than their previous sound engine, AHL. Don't know what that means - 8X faster clock, 8X more detailed samples, or just some copywriter manufacturing a number out of thin air. But, given that there's a new sound engine available on some Casios, it's possible that they may introduce a new version of the 7600 with the new sound engine within the year. I'd be very angry with myself if I purchased a WK-7600 simply for the fun of having something new - and then watched the unveiling of the 7700 at summer NAMM, complete with a ton of new samples and more rhythms.
So, given that I already have an aging Kurzweil and a soon-to-be-repaired YPG-525, I think the best thing for me to do is to hang back, get my music room working, and then do a real evaluation of what my needs really are. It might very well turn out that all I really need, is motivation.
(But I reserve the right to buy a CT-X700. It's cheap enough that it would allow me to evaluate the new sound engine at length, and hear for myself how it sounds compared to my existing gear.)
And on a completely unrelated note... Alberta is under a cold weather advisory right now. I've lived here all my life, and I tend to ignore such advisories; I generally feel that I have a pretty good understanding of what the climate will be like. Well... it appears that I've given my feet a mild case of frostbite. Nothing major, just the constant burning sensation you have with a low grade burn before the dead skin peels off and you're back to normal. What I found surprising is that I've lived here for more than 50 years, and never experienced this. I guess the message is, pay attention to the weather advisories. Hopefully you can avoid the consequences of my particular brand of silliness.
Take care, all - Charlie