bdunbar, I'm glad your hit rate went up! Again, I suspect the 400 is inherently slower to focus. The version 2 is probably faster, but at much higher cost. Sounds like you had the right attitude, and made it work. That's part of being a great photographer, it seems to me! The point is, you as the photographer are compensating for whatever your tools lack, and getting the job done. When the job is done and you get the shots you want, the problem is solved!
Thanks, yes I know about fooling it in manual mode, but then you wind up with under or overexposed shots that you have no control over. Sounds like the 1DX works the same as my camera. I know the whole point of manual mode, is that the user is responsible for getting the correct exposure...I just feel like, being able to use EC in this mode, with auto ISO, wouldn't be that difficult for Canon to implement, if they wanted to. Maybe it is, I don't know.
Some of my work consists of shooting at 1/2000 shutter in bright daylight, and I like to close the aperture to f/8 to f/10. I defined the ISO range in auto (which only left me with choosing ISO 800 or 1600 as the upper limit...I wish it would have let me choose finer increments, like ISO 1000). My shoot went fine...it worked...but sometimes there are "less important" highlights that get blown out a bit more than I like (and I prefer to not use HTP, because it seems to add even more noise in shadows, than a slight underexposure and lift later in post, achieves). But in ISO auto in Manual mode, there is no control over exposure. It will fire if it goes under or over by a bit (where in tv mode, it might not...assuming the shot happens at the edge of, or outside the specified ISO range in auto).
My shots at ISO 1600 are more than clean enough for my purposes anyway via the 6D, so I guess I'm just being a control freak. Cheers!