Backstabber brightens up my day every time I play him. He brings a lot of what I want in an X-Wing pilot: He rewards good piloting, pilots an iconic craft, works well both as an agressor and a pawn.
He plays with an open hand (get me in arc or pay, which can work both as an actual strategy and a nice mind-game diversion) and comes with a pre-built fluff list alongside Vader and Mauler for a trench run reunion to pit against Luke, Wegde and Biggs.
Sadly, that doesn't make him the best of choices in most matches, as the shortcomings of the basic TiE are well known by this point and he doesn't do anything to counteract those, but he ist and will remain fun as h*ll.