POLL: 5D mkIII high ISO

So I am wondering about the high ISO of the 5D mkIII. Some say no better than mkII while others say about one stop better.

I shoot weddings, so one stop is huge. It might mean that I could use my 70-200 2.8 IS in lower light, wich would be sweet.

So to those who have compared there mkII to the mkIII using ISO 6400+ and ONLY in RAW and low light please let me know what you think and if it is actually better or not.

Thanks