I know the issue with scrolling and was even able to come up with that (lame) excuse myself though this feels lot more like a software than a hardware limitation (the iphone just seems to be more clever at showing the user some uprezed cached image while its generating content).

What I'm talking about though is more serious than less-than-snappy scrolling. I'm talking about grinding to a halt when switching applications or music player stuttering terribly while trying to start up the web browser or missing a call cause the phone app can't load fast enough. It all smacks of swapping stuff in and out of memory. I think the N900 apps are too memory hungry and very poorly optimized, especially the music player.

For me this often makes the phone unusable so I have to kill off all apps I'm using and I've even taken to rebooting. Are other people having the same problem?

No developer should find this acceptable.