Mike (Hockeyman) extensively uses the Sigma 50/1.4 on his A99 --- Most of his recent shots were taken with that lens.
I have the Sony 50/1.4, which is a fair bit cheaper. I got it used for $250. According to most reviews, the Sigma is better. But the Sony is cheaper and smaller. The Sony is still quite good. It is a bit soft wide open at 1.4, but it sharpens up significantly from 1.7 and smaller. Far corners remain soft on full frame, but should be just fine on the APS-C A77.
I'm almost positive that the Minolta 50/1.4 has the same optics as the Sony 50/1.4. It may not have the newer coatings, so it may have worse CA and flare. It also won't support in-camera jpeg lens corrections, if you care about that. So it is almost the same as the Sony lens, and I think you can find it for $150 to $200.
Very much amateur photog here with a question. I have a Sony a55 camera and among the lens I have is a Sony 50mm f/1.8. I was debating on getting a 50mm f/1.4. I will use either lens for primarily dark rides at WDW. Is there enough of a difference between the two to justify the purchase? My skills leave a lot to be desired and need more practice but I'd rather practice with the f/1.4 if it will be that much better. TIA for you comments, info and tips.