How can one decide now, If we know afaik more or less nothing specific about the N9? Apple stuff however is out of question. Android? I don't know, its something I have to jailbreak and the apps are usually programmed in Java. This is nothing for me.
My N900 is just a month old and I want to keep it for some years, so my next smartphone wouldn't be the N9 anyway. A new smartphone should be at least that free as the N900 too.
I couldn't really test the handset edition of meego on my slow sd card, but if it isn't crap, I will probably install it on the internal emmc with or without Nokia support.