-Speed Boost makes it a douche to revenge kill. After 2 only insane stuff like Jolly Excadrill in sand can outspeed it, and you need REALLY good priority to revenge. (It resists Bullet Punch and Sucker Punch, Mach Punch only hurts its its from something like Technician Breloom, you need Aqua Jet or a super strong Extremespeed.)
-Huge offensive movepool, including TWO base 120+ power STAB moves for both physical and special attacking and a large array of coverage moves.
-Sunlight support lets it muscle past its counters with Flare Blitz.
-Speed Boost + SD = oh dear, and it can go mixed for unpredictablity.
Pretty much 4th gen Salamence if Mence had Speed Boost and Swords Dance is what I'm trying to say.