Not sure where you are shopping keferen but on amazon.com

N9 16GB = $649 ($609 if you want lightly used)
Galaxy S2 = $540 ($450 for used)

Thats much less than $300... The S2 has also been out for a while, a galaxy nexus which is the new phone costs $749 right now on expansys and thats only for the 16GB so not really a good comparison!

There are differences between these devices too such as the pentaband radio which in the US is huge as it opens up both TMobile and AT&T.

Yes the galaxy s2 is the top of the line android device but I owned a single core 1Ghz android phone between my N900 and N9 and there was no comparison. It was a very slow and frustrating experience even with custom ROMS..

The N9 is far from perfect but swiping is great, the UI is smooth and there are some apps for the phone on the app store... I wish there were more, to me this is the major drawback and its only a minor one as theres only a few I wish I had for the N9 (shazam, web2sms/chomp/bitesms (web2sms is coming in the next week to the store))...

There are also new apps all the time. The device is far from perfect but I am very happy with it for now.