Overall condition is important but is completely up to your standards of what is acceptable. Phantom is really a hard title to come by. Playfield wear (as stated in previous posts) around the edge of the mylar, wear around the outlane switch holes, etc.
I personally wouldnt pass on any Phantom of the Opera purchase (various conditions) if the price was right and you were happy with it.
The biggest deal besides the playfield is the backglass, as it was screened on both sides and the front is typically damaged.
The backglass on your potential purchase looks very good.
Good luck with your POTO.