If I had to choose, I would go with Miley Cyrus how she is currently. I think she seems a lot more genuine and true to herself now than she used to be. With Katy, I've never really liked her or her music. I mean, I'm not a huge fan of Miley's music either, but I did enjoy more of her songs than Katy's.
Not a super fan of either, like they both have good songs and bad songs and have been both good and bad in the past as people? As of right now, Miley is on an upward trend and Katy is heading back down imho.
I used to love both of them but now I hate them haha. I grew up with Hannah Montana! Those were her best years. I supported her when she was getting into more adult music and her Youtube show with her best friend/backup dancer. I liked some of Katy's music even up until Prism but I find her extremely shady and annoying. I find Miley opportunistic and also annoying.
They don't seem very likable as people, but I guess Katy has been more bearable overall.
When it comes to their music, I prefer Katy much more. Though it seems like they're switching places with their newest albums.
But I still prefer Katy's voice much more, never liked Miley's singing voice but it was bearable with We Can't Stop/Wrecking Ball.