Marc Alhadeff from SonyAlphaBlog tested the new Sigma 56mm f/1.4 and concludes:
“The Sigma 56mm F1.4 DC DN Contemporary (430 euros) is (one of) the best lens available on Sony APSC and will do superb job for portraits. It is the equivalent of an 85mm F1.4 on a full frame cameras. During a blind test most people to whom I showed results thought photos were taken on a full frame cameras with an 85mm!”
Lenstip also tested the lens and concludes:
It is another excellent optical instrument, offered at a sensible price; it shows that pricing of other producers of mirrorless devices is really over the top.
And here is the video review from Digidirect and Dunna Did It