sigma 150-600 contemporary

[dindsy]

hi there,
i'm looking at a new lens for sports and bird . so the 150-600 is in mind.
i am looking at the Sigma contemporary because it gets finance approval sooner. A friend says get the sports.
I've seen some reviews and shots from the c on this forum. Is there any paricular concerns i should be considering with the contemporary?

BTW. its to go on a Nikon D750

thanks