itsastickup: The Sony system is very attractive but for one issue: none of the pro/semi-pro zoom lenses have great bokeh, and some are downright awful. Canon lenses thrash Sonys at bokeh.
I really do want to buy in to Sony but this issue is a show-stopper.
Canon 70-200 2.8 L IS II USM review (dpreview):
Background Blur ('bokeh'): This is one aspect of the lens's character which looks like a step back compared to the older version - the bokeh has a tendency to be somewhat more 'busy', with harsher edges and less-smooth transitions between out-of-focus elements.
Sony 70-200 2.8 G review (dpreview):
Background Blur ('bokeh'): On the whole the 70-200mm F2.8 G produces very pleasing bokeh across a wide range of real-world shooting conditions - we'd consider it one of the nicer fast telezooms in this regard. About the only time it trips up is when faced with complex distant backgrounds, and shot slightly stopped down, at which point the bokeh can look a little harsh.
And Sony 135 STF is the King of Bokeh. Canon/Nikon does not have anything like that.