Both Lolalytics and Champion.gg are considering her one of the best champions in the game atm in overall performance rating. Her last direct balance change was in 9.18, and she didn't have this performance the whole time though. What changed? Does Bot Lane's meta just favor her this patch or did someone discover something cool about her?
A lot of people have been running Klepto on her now (it's her most picked rune according to u.gg), and probably ADC powershifts with Riot finally nerfing Kai'Sa and Xayah who have been the top tier ADCs for a while now and Ashe who got needlessly buffed.
They've also started running triple or quadruple 
. Sometimes even 5 with a BF sword asap lmao.
Its absurdly gold efficient and gives her a lot of staying power. Best part is you aren't even effectively losing gold because Klepto is so broken. Good thing its getting removed. She'll see a drop in performance with its removal because this won't be as viable anymore.
i'm an m7 mf and everything people say to run on mf I never use. klepto? nope. I run electrocute. doran blade? not in my kit. every game I run with mf I first rush 
then start building 
. i usually finish 
by the time it has finished charging or close to being finished and as such is usually my 5th item. by building early i can acquire more mana allowing me to stay in lane longer. plus mana flow band helps with mana too. when i have my full kit my ult does over 6000 damage with a 45 second cooldown. though i usually end up getting to when the game ends.
She's been going crit and abusing klepto for a mid-game powerspike.
Shes pretty bustd, i just played her first time in a normal game and got 30 kills like if the entire enemy team is squishes a auto q auto will like 1 shot most people after you buy a dirk. her ult does so much damage that the full wave of bullets at full build does over 7000 damage. shes one of my least favorite champs and i was even right clicking akali/rengar to death while we were both full builds.
MF will lose some winrate once Kleptomancy disappears in a few days.
She was, is and will always be a solid pick for ADC. She doesn't have a particularly weak state in the game, her R is awesome at nuking the enemy team and she has multiple viable builds. She is also extremely fast and bit hard to catch.
