Tiles with Square Lay-In are the easiest to install, but the visual effect of tegular, vector, or tongue & groove are interesting and appealing to many people.
The combination of grid size and edge profile will affect the visual appearance and ease of installation of your suspended ceiling.
The Grid are the lines you can see between the ceiling tiles.
The standard width is 15/16" wide metal frame around each tile – about the same size as the diameter of a Quarter. A narrower version, 9/16”, is also common.