AF problems on 50mm 1.4?

I got a 50mm 1.8 for Christmas. I had seen a lot of online talk about the AF problems, and mine definitely has them. Since a lot of people have talked about replacing the lens once, even twice, and still getting replacements with the same AF problems, I was wondering about replacing it with a 1.4. I haven't read anything online about the 1.4 having the same AF problems as the 1.8 but I just don't want to trade up ($200 up) for the same problem.

Does anyone have experience with this?

Thanks