Thew new improved version is now available for preorder at Adorama (Click here).
SonyAlphaBlog tested the brand new Samyang 50mm F1.4 AF II and concluded:
The Samyang 50mm F1.4 AF II is a huge upgrade compared to the Samyang 50 mm F1.4 AF. It offers overall very good to excellent performances at a fraction of the price of Sony Planar T* 50mm F1.4 Zeiss or Sony 50mm F1.2 GM. Its main weaknesses compared to the Sony are : the AF that is a little bit less efficient and the bokeh balls that are not circular when aperture is closed down + a higher level of CA