So I got lucky and got Xayah in a 1700IP lotto. And playing her in a botgame I noticed her W gives her both attackspeed and double attacks (at 20% strength). Which makes me think that On-Hit for that insane burst would likely be just as good as the normal build. In fact, I am starting to consider they changed BotRK with her in mind.
LankPants2 votesThe double hit doesn't proc on hits, I could see BotRK being good on her right now though, mostly because it's a broken item.
PureSilvrr2 votesI think the W is On Basic attack or something like that, not on hit, so an on hit build really wouldn't work.
Very Hard Engage1 votesits not that great, shes much more of a bursty champ who benefits a lot from crit and atk speed.
like i see her mimicing kalista or twitch builds to be maximally effective.
Myrkrvaldyr1 votesA weaker version of Kalista, Kog and Twitch. She has attack speed but no where near those 3. I build hurricane on her, it's a very good item on her, I've been trying bork, it's pretty good, too. Shiv is also good but situational. She's like a MF with more natural speed. I'll try a Quinn or MF-like build on her, with cleaver and all and see what's up. Right now, after 34 games (already have her lvl4), the recommended build is not as effective, especially that Fire Cannon, it's useless. One thing is true, though, once you hit around 350 ad, her E with at least 5 feathers hurts a lot.
Very Hard Engage1 votesbork -> hurricane -> IE
sometimes essence reaver
pretty core if you see all the winning builds
basically just look at the people who get wins or actually pop off with her.
qtpie is going ie -> pd -> ER and does well with it.
sneaky is going bork hurricane every game
Myrkrvaldyr1 votesI just tried an interesting build. Standard ADC runes focused on AS and 
She hits 3400 hp, 305 AD, 1.46 AS and 1.77 with W, only 20% crit but when it procs it's double, 17% life steal. Quite cancerous to me, but I need to be in an actual fight and see how much such build actually helps her, if she could fight 1v3 at the very least.
I also tried a full life steal build, 47%, very squishy but huge sustain and speed, but with CC she'd die very fast, not viable, I bet.
Escheton1 votesI just tried an interesting build. Standard ADC runes focused on AS and
I also tried a full life steal build, 47%, very squishy but huge sustain and speed, but with CC she'd die very fast, not viable, I bet.
I am trying to get her in toplane, just for this kinda thing.
Myrkrvaldyr1 votesBut she can't solo Baron with that build, not even with the elder dragon buff. Damn that monster hits too hard.
MysterQ1 voteshttp://koreanbuilds.net/champion/Xayah/Bot/7.8/2088485 Closest thing to an on-hit build. But really it is just because Bork and Hurricane work. Decent win-rate. A few other Koreans are using Bork and Hurricane, but then build less on-hit items. Figured the Black Cleaver in number 1 made it the most on-hit.