Scott,

I think by now most of your queries have been answered.
I had the PA80 and later on the PA80 for 5 years. Over the last
two years I went from PA500 to PA800. The touchscreen is a complete
marvel particularly for those like me who program a lot. Which brings me to a point that should be of main interest to you in your decision to buy the Micro or not. ( or even the PA500). KORGS demand programming.
Contrary to the Tyros you need to tweak etc.etc. if not you get easily bored with it. That is why I spent hundreds of hours tweaking and progamming , that is why people remark it seems like they have gotten hold of an entirely new keyboard once they have loaded my programming. (Ask uncle Dave, he had my PA800 programming a two years ago and that was even much inferior to my present 2012 set for the PA800).
There is stuff on the internet from me that you can download for free and use on the Micro. And there is other stuff that I have which certainly makes the PA50/Mikro shine, see my webpages on page 7. With a Tyros 4 at home and a little bit of pocket money at hand I would ALWAYS go for the Mikro at that absurd streetprice. And do hook it up properly like I suggested to the Tyros, both MIDI and AUDIO.
What do you stand to loose ? And that goes for virtually most of you !

good luck,
John Smies

http://pasounds.intropagina.nl/