jgpaiva: No, the pm you sent me doesn't change either of the two quirks I've described above.
With a little more use under my belt now, maybe I can more precisely describe the quirk in response to which you sent me the pm:
If, when trying to left-button-drag (ie invoking GridMove) a window to an open spot on my monitor (ie where I can theretofore see Windows desktop) in order to snap it to a distant grid position, my dragging mouse crosses a pre-existing window in between, the window I am dragging jumps back to the location from which I moved it, and my GridMoving mouse instead picks up the window I cross and moves that latter window to the empty space on the monitor I'm dragging to.
I seem to encounter this problem whether or not either the window I'm trying to drag or the window I drag my mouse pointer across on the way to my destination, or both, is a previously-snapped-to window or instead a new window that has not yet been snapped to any grid position.
If I can carefully drag the window I'm trying to move so that my mouse pointer itself doesn't cross any other window, I can successfully move the window I'm trying to move to the destination to which I'm trying to move it. So I either need an open path (ie no windows) to move along, or I need to first either drag intermediate windows out of the way or temporarily Minimize them--ie get them off my screen.
Great product. Very usable in its current state.