I don't get why people compare the 24-70 II with the 35L... Makes no sense in a way. Very different uses.
Comparing the 24-70 and 24-105? Sure.
But the 35L is a fast, wide angle prime. Capable of shooting in near darkness. No matter which way you cut it, the 35L will ALWAYS have 2-stop benefit over the 24-70 in low light. Even with modern cameras amazing ISO, the 35L still will allow 2 stops ISO less (meaning more DR, less noise, etc...) and the ability to match that ISO the 24-70 II is at with 2 stops of additional shutter speed. Meaning at ISO 25,600 at a SS of 1/50 with the 24-70 II, you can either shoot that same SS at ISO 6400 or at the same ISO, have a SS at 1/200. You won't notice all that extra resolution at ISO 12,800 anyways!
Sure the 24-70 II will most likely out-resolve the 35L and many other primes it appears... But the zoom will never give f/1.4 low-light ability and the bright viewfinder when its VERY dark.
If you don't push the limits of night shooting, the 24-70 II will be the better choice most likely. If you do, the prime is an invaluable tool and the zoom will not have anywhere near the same capability.