Can't say I've used Aegislash much myself, I rarely try Ubers, so I'm no expert. I've seen it several times in BSS, though, and I have one in-game specifcally to wreck the Maison. One thing I've noticed about it that stands out: Aegislash provides excellent defensive/switching synergy with several higher-tier dragons. While it might seem like an odd choice, Aegislash and Hydreigon get nearly perfect defensive coverage together; Aegislash resists everything Hydreigon is weak to and vice-versa. It also synergizes well with Garchomp, which doesn't take Aegislash's weaknesses as well but is immune to Thunder Wave.
The nice thing about Aegislash is that it can go with special or physical attacking options to better pair with the rest of your team. Defensive variants also have merit, but Aegislash only gets recovery via Rest or Leftovers. I find Weakness Policy variants to be the hardest to deal with, anyway. The downside is that it is extremely vulnerable to status and other non-damaging moves; it hates paralysis, and burns just destroy physical attacking variants. King's Shield doesn't protect against status moves, either. It's too slow to stop the opponent's support 'mon, too. Trick Room, while rare, doesn't completely derail Aegislash, though, so that's a plus on the low speed.
The risk I took was calculated, but man, am I bad at math.