Between Satio and N900 the choice seems really easy, it took me only a few minutes to rule out the Satio from my shortlist.
N900 is superior in almost everything, even n900's camera clearly does NOT suck, its video function is way better than the Satio's, and a battery of merely 1000 mAh on a smartphone (satio) is a no-go to me.
There are few things that I miss on Maemo/n900 coming from my dear old s60-powered E65 - things that almost go without saying in a fully matured smartphone OS like Symbian (not withstanding that it matured during a period where touchscreens and usability were not top priority for manufacturers). Global device search - Native google maps application - One-handed texting - Java - ...
However, it's important for you to look closely at how you want use your phone, what are the most important things for you to do with it. Each and every phone on the market has its pros and cons, and the things that are inmportant to me are currently done best with the n900...
my N900 top features are:
internet browsing (Micro B plain rules - with flash!)
hardware keyboard
awesome hardware specs
decent camera with lens cover, !with dual led! and !quality video! !with video light! !manual video focus! (try finding these features in any other smartphone....)
Maemo OS
Multitasking

to be continued...