<rhetorical question> So which of the tab button locations is well designed, and which is not? </rhetorical question> It doesn't matter which one is used, so

<rhetorical question> So which of the tab button locations is well designed, and which is not? </rhetorical question> It doesn't matter which one is used, so long as the application sticks to the platform conventions, and for the actions that don't have platform conventions, picks bindings that don't need you to be a finger contortionist. It doesn't matter if the 'ok' button is to the left or right of the cancel button, but if a UI designer swaps them around relative to what the platform normally does, he's just designed the UI poorly. If 'q' exits a command line app normally, but the developer makes 'esc' exit his app, then you just made a poorly designed UI.