IQ 50mm 1.4 vs. 35mm 1.4

I'm contemplating saving up for a 35mm 1.4 for my 5d Mii. However, my decision to get the 35mm 1.4 would be very much dependent on the IQ over the 50mm 1.4. The focal length differences is something I could live with.

Would you say that the 35mm 1.4 has better IQ than the 50mm 1.4? A lot or just negligible.

I would appreciate your opinions on this. If I get the 35mm than I'd probably sell the 50mm.

Many thanks in advance.