I've been using SD Maid as my go-to cleaning app for a while now, and have been thinking of going premium. So just decided to do a last minute check to see if there were other better apps out there, that's when I came across Clean Master. I must say I was rather impressed by the UI, so here comes my question/doubt - it's free. I mean, it could be nothing, but why is it free? How is the Dev making money? Is it on ads and if it is I'd rather pay for an ad-free version, which doesn't seem to be an option. Now, I've noticed that it is one of the top apps with a huge number of downloads and this is usually a good indicator of the safety of an app, but I i couldn't help but notice a couple of red flags. Secondly, I wasn't very comfortable with the "Draw Over UI" permission, why is this required? Speaking of which, I've been very wary about this "Draw Over UI" permission as I've heard it can be used to phish data? How much of this is true? Coz I have refused to download a lot of apps due to this one permission - some notable ones being Pocket and some Screen Dimming apps. So when it comes to SD Maid vs Clean Master, what's your choice? Or are there more options?