Considering buying a 1D MKIV , I was wondering if anyone has had much experience with this model,already have a 5DII and 1D MKIIN(would trade this or sell it) love the MKIIN but I am enticed by the higher frame rate ,low light possibilities ,the improved focus abilities and the dual Digic 4 processors. Mainly use the MKIIN for sport and wildlife but like the idea of using the MKIV along with the 5DII for indoor work(functions) and portraits. So any comments from owners or people who have used it would be appreciated.