Quote Originally Posted by Oren Grad View Post
Three things I most worry about with QR's:
1) How secure is attachment of plate to camera? Will the plate tend to twist or otherwise loosen, without warning, under routine handling?
My is secured by screw, it's never coming off unless I decide to remove it.

Quote Originally Posted by Oren Grad View Post
2) How easy is it to attach camera-with-plate securely to the QR base on the tripod head while on the go? How easy is it to get it wrong, and thus end up with an insecure mount?
Depends on the system used. I like the FLM clamp because I can put the camera in from the top, not from the side, where you have to wiggle it around to get it to fit in just so.
Once I drop the camera in from the top, it's mated to the clamp, but can still slide back and forth along the clamp. Tightening it securely means flipping the lever. The lever has a spring so it can be pulled out of the way of all the action.
Removing the camera/plate is done only by having the lever in its neutral position and pressing a button.

Quote Originally Posted by Oren Grad View Post
3) How vulnerable is the clamp to unintended loosening?
As I said above, the plate will not come off the clamp unless both the lever is in neutral position and a button is pressed.
When in use, there are two safety catches in case the lever gets bumped back and forth, but even then, the plate will stay on the clamp.

Different manufacturers use different systems of tightening/safety/release; it's worth looking into those differences if you ever decide to opt for this kind of system.
I find this system to be great for LF as there's no screw to tighten, making it faster to operate, and placing the camera in from above is faster and much safer to use.