Sigma 50 f/1.4 -AF issues resolved now?

I'm considering getting a Sigma 50mm f/1.4 for use with my 50D (the camera store recommended it over Canon's 1.4 and definitely over Canon's 1.8 version), but have read several tests/reviews/user feedback that despite its better build and sharpness over Canon's it suffers from severa auto-focus problems.

Seeing that most of these reviews are several years old and it would be in Sigma's own interest to fix it I'm wondering if this is a non-issue if buying it now (new, in the store that is)?

I'm considering this particular lens for a newborn session in a couple of days and otherwise portrait photography in general -mainly for the shallow DOF in addition to using it with low natural light, but also for less (none at all?) problems of perspective distortion than other focal lengths (i.e. exaggerated features of the subject when being close to the subject). I understand this is because 50mm replicates what the human eyes see, and it's related to the physical lens itself and not the FF vs. 1.6x crop factor filed of view of the sensor. Is this correct?

Lenses I already have are:

• Sigma 17-70 f/2.8-4.5
• Canon 70-200 f/4L
• Canon 35 f/2