I have owned, up until recently, the Minolta 50mm f/1.7, the Minolta 50mm f/1.4 and the SONY 50mm f/1.4
I sold the f/1.7 ... so you figure it out.
Comparing the Minolta f/1.4 (if you could get one) against the SONY f/1.4 ... the SONY is a tad bit sharper, overall. That swing to f/1.4 from f/1.7 is just hard to believe. If I had not witnessed it, I would not believe the difference in exposure level.
Now, remember ... I have BOTH f/1.4
s ... I bought the SONY because it is sharper, faster and has the eight pin contacts. It costs more ... but, it flat out delivers in low light. If you have only one to buy ... that would, hands down, be my choice.
Good luck with your lens choice.