Use a tripod if you can. The depth of field is so shallow that slightest movement handheld could render the subject out of focus.
Shoot at 1.4 and keep your expectations regarding sharpness and contrast sensible.
It will have typical fast prime characteristics when shooting wide open.. It will be fairly sharp and lack a little contrast. Both easily remedied by applying a little sharpness and one touch auto contrast in any free image viewer (ie. Faststone)
The bokeh will be delicious though. That 9 bladed circular iris really does make for creamy bokeh, that in my opinion, is unbeatable for the price.
Stop it down a couple of stops to around F2 - 2.8 and its very sharp. Colours, contrast and bokeh amazing.
I've just sold mine but regretting it in a way.
I didn't use it all that often but got really nice shots when I did. I should get out more but just a bit busy for my hobby at the moment.
Hope you get a good copy Jason.
You should still be able to return if you don't.
These lenses were really hit and miss for QC. I had mine calibrated at Sigma for around £50 all in.
Shame about the QC because its an amazing lens if you get a good one.
Spanks the Canon 1.4 and 1.8 (although the 1.8 STM is supposed to be very sharp wide open and bokeh a little better, but still not as nice as the Sigma's)
Tony.