Having seen the feature in Unreal Engine, it would be awesome if the sizes when resizing an object and the location when moving an object snapped to the grid. The grid/snap frequency would be adjustable by a slider/textbox. I've already requested a similar change for the rotation widget, it would be really helpful to have it snap in increments according to the same slider/textbox.
Here's a video showing how UE does it (if it's of interest), their interface seems to be extremely user friendly.
https://www.youtube.com/watch?v=KQ1zuL2PWtk