I have had the FA 50mm 1.4 and didn't like it that much. It's not exactly super cheap and doesn't offer much at 1.4 imo (it's a little soft and has a lot of CA). I much prefer the F 50mm 1.7, which you can get for not much money. It's sharp from 1.7 and I really enjoy the rendering which remind me of film picture (call me a wannabe if you want, I shot film once in my life, and it wasn't even with an slr). If I had to put words on it, I'd say it's the out of focus transition that I find very pleasing with this lens.
I was kind of in your position a month ago when I had some paypal money to spend on a lens. I wanted the FA 43mm simply because I wanted to complete the trio. However, since I had the F 50mm 1.7, I wasn't sure if it made any sense at all, and I really didn't want to sell my 50mm anyway, cause I love it. Well, in the end, I figured I really wanted to own the 43mm for it's special rendering, and since the F 50mm 1.7 doesn't cost a whole much, I decided to keep both. Although I'm very happy having both lenses, I still don't know if I will find use for both lenses... time will tell
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Good luck with your choice.