But you will love the quality and low noise reduction at high ISO on Full Frame cameras. That's what made me switch. **** I can't imagine carrying around a 600mm lens...
Yeah, but fast moving bikes/cars/planes require a good autofocus system and fast FPS capability.
The only full frame that really fits that is the 5DIII, and I got way too many other things that need the $2500 than a camera body.
I really want to save up some money and get a real underwater rig. Either a housing/strobe for my 7D, or a bridge camera/housing/strobe. Something like a G-series or RX-100.
For the cars/bikes, watch your reflections. You want clear highlights and not be able to see anything in the paint.