We do have a snapping to grid feature.
On the on screen info. On the Right hand bubble, click on the first icon.
Activate grid snapping. Then Set the grid snap distance to what you need. 1 meter is usually the best for box etc...
If you already have an entity in the scene before activating grid snap, then you will need to set its position x,y,z to start on a whole number. Then with snap activated, you can drop new assets in the scene and they will align to the grid.
There is also a rotation snap.
Hope this helps