What to buy: 5D MKIII vs 1D MKIV

I currently have a 7D and a 1DmkIII.  I prefer to shoot with the 1DmkIII over the 7D due to the better files and to me the better AF.  The 1DmkIV should give you even better AF and files.  I have only shot my friends 5DmkIII for a short while.  Great camera but it certainly doesn't have the build quality of the 1D series.  You would get a bit more reach with the IV as well.  If it was me, I would go for the 1DmkIV.

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Chris