Almost every one who has switched to the AF-on control of the AF start has stuck with it. There are many reasons. One, it separates the AF function from the shutter release so leaving a camera on AF-C mode allows complete control of the AF. A static object is focused on using the AF-on and released as soon as focus is obtained. Releasing the button locks AF and you can recompose, re-meter etc and fire the release was desired. With a moving object, AF-C tracks as long as the AF-button is down.
On the D7000, AF-on does not start VR but on the new pro cameras it does(one reason battery life from a D800 is not as good as hoped). For action, the AF can be kept tracking while until the release is pressed just by holding your thumb on the AF-On button. Setting AF-C release mode to Focus means it will not fire until the subject is focus locked, but setting it to "Release" means it is ready to trigger immediately when the shutter is pressed, without waiting to refocus as in the case with using the release button for both focus and release. With holding the AF-On button, it is already focus locked so a new AF cycle is not needed. Sports and action shooters will be faster camera response that way.
All pro cameras have a dedicated AF-on button because it is the preferred mode of focusing for most action, wedding and event shooters.
It takes a few hours to become accustomed to using another button for AF initiation but after that few people ever switch back to release button AF start. The only time it is a problem is when allowing others to try your camera, unless they are familiar with the concept they will end up with blurry images. But that is OK also.....they will have more respect for your in-focus images;>)
The only downside for using AF-C as default mode is in low light the AF assist light is not active. The visilble white light from the camera AF assist is not usually desired but the patterned, modulated IR assist light from the SB900 etc, shoe mounted flash IS desired most of the time. So I set one of User banks to low light AF-S for flash work, which also switches to M exposure mode, which is always used for flash when it is the dominate light source. A and S mode work fine in TTL BL mode for dealing with back-lighting and good ambient fill light from flash.
Stan
St Petersburg Russia

Visit my Nikonians gallery.