NOTE: there is a shiny silver "A" on the side of the lens in the picture, meaning this is their "Art" line of lenses - the same breed as the 35/1.4 that has blown away many many people.
It's also proof positive that the pic is a fake. IIRC the Art designation is for lenses with a large maximum aperture.
It should be 'contemporary' (C).
Still, I think the lens might be real. Calling this 'A' vs 'C' appeals to the people likely to buy the lens so it makes sense from a marketing perspective.
Lacking however, as with the 35mm: Weather sealing...
And (if this Sigma is real) there's where the 24-105L still wins as a do-it-all travel lens. India would have killed my camera/lens without weather sealing!
5D3, 5D2, Sony α6000 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: SY12 f/2, Ʃ19 & 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses.