i bought the lens soon after receiving the 50 1.8. many similarities and some improvements compared to the 50. excellent center sharpness wide open, good flare resistance, good autotofocus, nice feel and design. the basics done right. a bit too much focus breathing, a bit too large but smaller than the 50, though both are pretty light, bad extreme corners [only visible in 3:2, not in 16:9] and some pincushion distortion. the hood mounting is much better now, but same old rear cap design with reverse rotation. minor design improvements since the 50 1.8.
for the l-mount system it's incredible value, given the prices of the af lenses already on the market. unfortunately on the older models with dfd af, the focus is slow, but not because of the lens. on the newer models with phase detection af, focus is smooth. linear manual focus not working, but focus transition works.