Mark I'm waiting for mine to arrive at present although I have seen it on my mates Nikon D50 (the whole reason for my buying it

) and the OS is incredible at 400 mm I was shooting 1/30th of a sec free standing and the images had NO camera movement/camera shake on them!!!!
Is it as good as the Canon L glass? Maybe not but you need to double your budget to get one of those.
I'll post back once mine arrives