[Klaus]

Of course  seems good, however there's no point of having razor sharp f1.4 lens if focus isn't accurate, for this lens focus is a true killer, so how does it perform on this side ? read this is being the weak point of the  sigmas

 

Well, it just shows a conceptual weakness of DSLRs. RSAs are fairly normal and DSLRs cannot compensate this.

However, let's be real - the bokeh fringing samples are taken at close focus distances. What you can see there in terms of RSAs it is amplified.

As far as general focus issues are concerned - yes, Sigma is somewhat worse here than the others but then they offer the USB dock for fine tuning.