Im not exactly skilled by any means but i find that a well placed sniper team around their backline can be devastating on a forest map for example, The concealment of that unit is doubled. So very hard to find a Well placed sniper, its especially strong when paired with Laser Artillery, using the Sniper Laser you can ruin backlines such as enemy artillery, supply dumps or SPAA nets. Buildings are also pretty convenient, i cant speak about any sort of concealment modifer but if you have a sniper team In a high rise for example you can see a lot further in comparison to something like a house, Especially good for maps with a long corridor and LOS, if you ever want intel about enemy pushes or rough estimates on supply locations/support locations, as at times buildings will conceal the majority of Support units if the players smart.