That 35mm L is an epic lens, from what I've seen or heard. It's just a shame it's ten times the price of the 40mm...OK, the 50mm is faster but I reckon the IQ from the 40mm is better. Plus, there's something about the 40mm that just 'works' for me.
If you find 40mm works for you and appreciate 50mm's 1.4 aperture, there is one lens suits you the best:
I've been in your position but 40mm wasn't really availably. I had 50 1.4 and 35 f2, I love both of them, the speed and image quality of 50 and the angle of 35, so after some mental struggle I sold the 35 f2 and got a 35L, that's the best decision regards to lens I've ever made.
Not 10 times the price, only 7