This software is crazy sweet and works really well with grid move...
I prefer to disable the semi-conflicting options in it though, like middle click on title in it - because i often middle click the title with gridmove
anyhow, AltDrag is great at helping you move windows in place, when you are not grid-moving... I mean, you often move windows around with grid-move but then sometimes you just want to drag a window the regular way, and since you have so many nicely aligned windows courtesy of gridmove, you can easily "pop" a window into place because it is attracted to other windows edges or edges of the screen. As you can see, explanation is a bet messy but one you actually try it, you'll see what i mean.
I guess what I'm trying to say is that the windows just slide into place easily... when moving or resizingGridMove + altDrag = a killer combination, basically nothing else comes close. I tried most of window managers out there.
I was close to purchasing a more bloated program called aquasnap because it didn't allow this type of thing with secondary monitors unless you paid, but alt-drag works on multi-monitors, is small and unobtrusive and free.
https://stefansundin.github.io/altdrag/