i waited about 2 months before the thing actually got delivered. I have been playing with it for about 18 days now...and i am talking hours at a time! I have read the manuals (and am still digging through the online version of it). please keep in mind I am still learning and don't claim to be an expert.
here are my initial thoughts/opinions
1) the choices of sounds within each section are a bit disappointing at first glance. the brass section in particular has very few trumpets that allow for polyphony (most are articulation voices and are mono only). the quality of the trumpet sounds sometimes have too much vibrato and there seems to be no way to change that. the flugel horn has a delay before sounding (breath sound happens before first note...still trying to work that out)
if you go into the main section, goto page 2, you will find legacy instruments....MUCH BETTER!!. but why they buried them there is a mystery to me---well at least they are there (the choirs in that section are good too)
2) the styles are not terrific....there is very little variation between a, b, c , d (sometimes little to no change!!). In addition, there is lots of redundancy between styles (epic ballad, 60's piano, and motor city ---variation D on all of these sounds very similar!)
3) yamaha support is horrendous....don't expect any help from them. I waited 30 minutes to talk to someone, and when someone did connect I was told they didn't have time to talk to me...someone would call me within 48 hours (no window of time given other than that....)
4) still trying to figure out how to edit my multitrack midi sequences....doesn't seem to be a good way to copy a span of it across multiple parts (that may be an ID-10T error on my part). there seems to be no way to insert, delete or move or copy block sections at one time (kn5000 could actually do this!)
5) i find i need to really tweak the sounds to get what I am looking for (it is possible but takes a good bit of effort). it doesn't have the editing capabilities i would expect, but I can still get what I want
6) sliders don't seem to be very responsive....sometimes need to nudge them up and down to activate them
7) no way to freeze volume of styles (change a style and it changes the volumes)---yes, registration settings will freeze them, but changing styles seem to change volumes even with registrations set.
overall, with a bit of work, it is a nice-sounding keyboard, but i am somewhat disappointed in the styles and the amount of effort it takes to get the sound i want from it