If the lob is clearly on one of the player’s side and he is in the position, then he should go for it.
But what if the lob comes somehow in between the two players?
Considering that the backhand overhead is a lot weaker and more difficult to execute, the correct answer would be that the lob down the middle should be smashed by the player who has the forehand closer to the ball.
For example: if both players are right-handed, then it makes sense that the left-side player should smash the lob that comes in the middle of the court. An exception is the situation when the left-side player is off balance from a previous shot. In this case, the other net player should run around the backhand (if he has time) and go for it.
Placement wise, hit all your overheads toward the closest opposing player or if you have the chance to contact the ball very close to the net then go for an angled smash (toward the alley and side fence).