It's actually pretty strange, since in VGC that set is more common than one would think. Suicune, along with things like Cresselia, is something that you'd dump as much defense investment into as possible; it's rarely used to attack and is mostly used for support. (Suicune has the Sheer Cold set I mentioned but it's also got Tailwind, which in VGC is incredibly good, whereas Cresselia has Helping Hand and Safeguard and a few other fun things.)
It's one of those things that stays on the field a long time, because people usually go after its partner first (why? because it's much easier to kill). I ran into 2 Suicune out of the 8 rounds at Spring VGC Regionals; the one that wasn't Sheer Cold ran a basic Suicune set with Scald and such, and I'm forever grateful to Gastrodon for the many situations he'd helped me evade that day that otherwise would have broken me. (If you're curious about what team I was using,
it's right here. As for how I did?
Here, on Sunday. I went a very respectable 5-3, losing to 2 Garchomp/Zapdos teams and 1 Virizion.)