I spent about 3 hours today on the Korg Micro and here are my thoughts .

First of all this keyboard for the price a great value, thay being said here is what I Think I have had lots of experence with arrangers 9000 pro, G70, s910, now Tyros 4 so this comes form that experence.

if this unit is used for fun and not pro playing it will work well I think if you are trying to compeat with the above keyboards it will be a disapointment Keys are very small but play very well, styles are ok some are better then others not a big selection but prob can find more I was not impressed by the song player so if you are going to use it for Midi Files it is just ok Yamaha still much better in my oppinion .
I found it kinda confusing to run out of the gate not as user frendly as yamaha Drums where Pretty good it will not work well with yamaha midi files there are serious maping issues and you will need to re map most of your song files if yopu use GM TUNE 1000 files they work much better so the midi file player a bit of a disapointment for me.

the one thing I was very Impressed with is the sound set Pianos and organs very good and the bar on side of keyboard controls the leslie action very good plus Yamaha should take note to do this so the organ sounds can be controled in this way The sound set very good in fact for 500.00 you would be hard pressed to find that anywhere thumbs up to korg for the sound , programing it after the learning curve should be easy but first impression seemed confusing to me reminded me of Casio and all the steps you need to do I have a Px3 and it seems like that a bit confusing at first after a 3 hour period I had it down pretty good but I did not buy it today i just felt it did not offer enough in the area of a song player and over all sound on the files I use most of my files are Yamaha comp so it did not work to well but for the price it is a great deal for the player who is just getting in or just want something new to play on but to use it in a pro setting prob not for me , but the over all sound of the patchs very impressive so for sounds i could see using it esp for the organ patches where yamaha is very week so I am mixed emotions on this little guy some will find it great some will not.