Upload & Sell: On
sigma 30/1.4 wont fill the frame on your FF body. that's the only con I can think of. (you prolly knew that)
I rather have the 30 on a crop vs the 50 on full frame, if those are the only lens options.
the sigma is smaller, and it feels better built to me.
they have a different 'look' to them, that alone might sway you one way or the other.
The 2 lens mentioned is definately open for discusion, as I am open to other options in there range.
Yes aware of the strong possibility of returning to Sig for proper calibration. for sharpness & AF or find a used one with no issues..