Actually many people and many so-called professionals or website reviewers always use "noise" as a benchmark to dictate how well a camera performs....
But when it comes to reality, how often does a person actually view the pictures 100% at 5cm from the screen or print them out in the first place?
actually my clients require beyond A0 for printing. the most recent was a picture of a floral design with complex grass details blown to A0 for some president's award competition.
also, the shot of the girl is in a brightly lit area. dont mean to disparage but 300D from 2003 also can give similar quality given such prime conditions. im interested to see in dimly lit conditions.

ISO6400 unprocessed, on a moving tram at f4

ISO25600 unprocessed movement from both object and myself at f4 again
by all means, i'm trying to find out the limitations of A900 at available light photography.