I use the 28 1.8 together with 85 1.8 and 70-200 2.8 is II on a 5D3 for weddings. I could not afford the 35 and the new 28 and 35 were not released yet. I do not like the 50 1.4 and it's semi-usm. I needed something wide and this is what fit the bill.
Now that I used the 28 1.8 for some time now, I can say that I am very, very happy with it, especially for the price. I use it 2.0 to 2.8 usually and it produces good photos, from my perspective
After a few years, when I will afford it I will get a 35 1.4 and a 14 2.8, but until then I am very happy with the 28 1.8 and 85 1.8