I would prefer radar off because it is totally impossible to flank anybody because they immediately (or 30 seconds later) know you are on their flank and can turn to place their frontal armor towards you. That means you are always going up against frontal armor which doesn't work too well for Allied tanks against Axis ones.
HOWEVER, many of us remember what happened in tank night back before the radar was turned on. With terrains based on European or Pacific tilesets there were so many trees you basically couldn't find anybody. You could be a few hundred feet from an enemy tank and not know it. Many people rightly complained that driving around blindly until they blew up from an unseen enemy was a less than ideal source of entertainment. True, that is the way it is in the MA, but usual game play in the MA involves a spatially confined objective of some kind and that makes finding enemy tanks easier, i.e. they are usually on their way to, or at, the objective. In AvA tank night there often is no objective to concentrate the action, just tank vs tank battles. On the other hand, the base take, or bridge defense/attack nights do have objectives that concentrate the action and make enemy tanks easier to find even without the radar.
