I know it's a weird question, it's just that since the rune went live, I think I have seen it once in my games. And I haven't seen it in any guide here either, so I'm wondering, generally which champions use it?
I have a build on Xin Zhao that uses Hail of Blades. It works really well because it procks his Q almost instantly. It really is a toss-up on whether it is better than the other options.
Nocturne. IMO the best user. Shaco for the same reasons : they build full lethality (damage) and scale very well with attack speed which they don't build. To a lesser extent Quinn or Diana, who have a similar playstyle but naturally get attack speed already. There aren't many autoattacking assassins in the game but it's definitely designed for them, not standard marksmen. Jayce could also be a thing. Or Teemo.
I think Rek'Sai could use it pretty well too since she's all about knocking up a target, attacking them 3 times and then biting them for true damage. Also Tahm Kench for the cheese.
In a shocking coincidence, I literally published a short article on reddit on this very topic today. Here's the link if you're interested in my thoughts on the rune.
TL;DR: It seems to be suboptimal on everyone currently but there are a few champions it might be good on in theory. If you ask me the rune needs another buff to compete with the likes of PTA, Lethal Tempo and Conqueror (and Phase Rush for a couple melee champs).
I think
TL;DR: It seems to be suboptimal on everyone currently but there are a few champions it might be good on in theory. If you ask me the rune needs another buff to compete with the likes of PTA, Lethal Tempo and Conqueror (and Phase Rush for a couple melee champs).