OK, not for publicity purposes or boasting but to explain my right for the qualified answer ))) - at the moment I use 3 setups as follows: FP-80/Kronos61/Motif at home, Kronos X73/SW at our studio and RD-100/Krome for small gigs. FP-80 was bought recently instead of RD-700NX because I'd like to play a piano with easy approach to the synth keys and screen, as close as possible to each other so I put my Kronos straight ON the piano body (using a single X stand with some homemade additional back support). RD700 wouldn't allow this with those knobs all the top around.
Having said this I assure you that you are on the right way, Roland piano+Kronos station make a very good couple indeed.
As for the demons:
1.Loading isn't loooooong, it is just looong, nothing new in the X, I have to endure it once a day. I wonder why they didn't "invent" a hibernation on the PC-based Kronos thus far? There is a hope for the future though.
2. I am using Windows-7 x64 Samsung Slate Series 7 PC with both my Kronoses and had no issue with any SW so far...
3. The weighted keys had many issues for a very special HW glitch, which is fully cured in the X. Moreover, some people suspect (me too) that the hidden goal of the X "upgrade" was that keybed problem. Anyway, the X 73/88 hammer keybed is new (slightly different even in action) and has no flaws AFAIK. The light 61 version has been quite good since dawn.
4. Joystick? what's wrong with it? It came from the previous Korg' tops, reliable and convenient enough IMO.
5. Those noisy fans apart from excited girlz - I replaced the one in my home K61 with a quiet one. It took about one hour and wouldn't break warranty - I can always put the original one back, the connector is the same usual 3-pin. X73 is quieter but as soon as I have time I'll cure it as well.
Hope it helps