I've been running a Scarf set on my semi-stall team, and it's been pretty effective. The low base power of its moves is disappointing, but it still packs decent power. Its abysmal movepool leaves room for both Psychic and Psycho Shock, if you're into that which adds some "mixed" versatility. The speed is super super high, so you can outspeed a lot of sun sweepers (no sawsbuck : /) and other scarfers such as Heracross and Flygon. Other pokemon you can get surprise kills on are Crobat and Weavile. Apart from the surprise value, it's pretty good at cleaning up weakened offense teams.
And of course, it provides Magic Mirror support. Otherwise you'd just use Zam.
And of course, it provides Magic Mirror support. Otherwise you'd just use Zam.