It's easy for me to say (having both lens) but it takes a lot to justify that extra 3mm which cost you more than $2k. Unless you're doing lots of real estate/indoor stuff then the 17-35 is more than adequate and equally as sharp.
For example, I did a school formal, 250 students, and the 17-35 was more than adequate for the wide shots and certainly more useful for general shots where the 14-24 was too wide.
The 14-24 was designed for the three lens market - 14-24, 24-70 & 70-200 and if that's the way you want to go it makes sense but alone the 17-35 is more versatile.