Hi Andrew and welcome to the Synthzone Forum.
There have been many posts on the forum with reference to the relative merits of both Keyboards. If you have the time, I suggest you scan through the posts over the last few months. As to choice, it's really a personal decision but if you are hovering between Technics and Yamaha, the only way to decide is to audition them 'side by side' in a dealer's showroom.
I have the KN7000 and am very pleased with it - but I am a bit of a dyed in the wool Technics Nut, having had all the 'Flagships' since the KN800.
I don't think the Tyros comes with the equivalent of the KN7000 recording software - maybe someone else will confirm this. The SD card facility on the KN7000 is a really big plus, making the Hard disc totally redundant. Access time is just a few seconds and backing up the card content to PC is easy and fast, using the card adapter which comes as a free 'extra' with the Keyboard.
I believe the general opinion is that the KN7000 is a bit more user friendly than the Tyros but again, I suppose it depends on the user's past experience.
One other thing, I understand that the Tyros does not have a built in speaker system.
It may also be useful to you to do a search on the forum for posts by a member called Scottyee. He has posted some very informative comments re. Tyros/KN7000. Just use the Search facility at the top of the page and search under 'User Name'.
Initially, try the following links : http://www.synthzone.com/ubbs/Forum25/HTML/001151.html http://www.synthzone.com/ubbs/Forum25/HTML/001221.html
Hope this Helps ... Happy New Year.