Looking For Some Input Regarding 1D MK III / IV AF Reliability

Hiya folks, it's been quite a while since I've been here, having moved to Nikon a couple of years ago ( I sure do miss this community, best photography forum out here IMO).

I'm considering making a move back to Canon. I still have to finalize this decision of course, which involves a few key details.

One thing I'm certain of is this one simple fact - if I do move back, it will be a 1D 3 or 4 in the form of a 1.3 crop.

When I moved to Nikon, the most current issue at the time was terrible AF issues with the 1D MK III. In fact, AF troubles is exactly what drove me away from Canon in the first place. I was shooting 1.6 crops at the time and this was before any in-body AF fine tuning was available.

I know there will likely be a mixed bag of opinions regarding my last statement, however, there's no denying AF issues did exist.

What I'm looking for is some input from those of you who own or owned ( especially any current or former Nikon shooter with a D700 or D3) a 1D MK III or IV. What can be said of the AF performance considering all scenarios? What I mean to say is accurate and reliable AF in difficult, selective situations, low light, servo for sports etc. Is the MK IV any better? The same? Still room for improvement? Did the MK III ever get sorted out?

I'm seriously looking for some experienced, honest, unbiased information. It would be a great help for me along side doing some (limited) testing at B&H.

- Thanks

im not positive but i do believe the Mark III did get sorted out and put on a blue dot meaning that is was fine. But dont hold me to this im not for sure

The MKIII, as a whole, didn't have the AF/submirror issue, but batches within a serial range did. Canon sorted those out through 2 different "recalls", and so if you pick up one that is in the range, and it has not yet been addressed by Canon, you can send it in and have them do the changes free of charge.

The MKIII is one of the leading low-light AF kings at this time, and for general photography both are very good. The 1D4 seems a bit better with its new AI Servo AF II algorithms though. Sitting in the store testing AF isn't really taxing the system for either camera though.

The MKIII issues were all around fast movement, especially movement toward or away from you.

Thanks for the input. I've still yet to do some of my own testing - hopefully I can soon.