I don't know why you keep on mentioning h264 btw, as I said I went back to mp4v for video. And I literally use the standard N900 profile but I changed mp2v with mp4v (no extra parameters at all) and mp2a with mp4a.
As a N900 owner I'd say that it is once it supports gstreamer - it runs absolutely flawlessly with it as far as I can tell from the brief tests I've run now.
Not at all - but I guess the Wiki page could be more elaborate about what codecs/bitrates one could expect the various devices to handle, and also mention that the streaming server easily could be the bottleneck if the playback isn't smooth.
I mean if the default profile in the current official release ran perfectly out of the box, I wouldn't be writing in this thread in the first place