Hey iczek!
I own the Sigma 65 and the Leica 24-90 and did a quick Studio comparission a few week ago.
https://1drv.ms/f/s!ApcdcIWzABFlg4RlIGDFMMsw27j3Ew
The fotos are not retouched. Only developed in Capture One.
In my opinion the pics are very simmelar. The Sigma is sharper. The Leica has a little frontfocus.