Manjaro is not arch though it likes to pretend it is and includes the aur. Because of this sometimes aur packages will break manjaro since they expect packages which arch uses that aren't on manjaro yet. Pamac, their software center, has broken the aur via essentially ddosing it multiple times. Also, despite the fact I have no idea what I'm doing ive never had my ssl certificate expire, Manjaro has several times. I'm sure there's more but that's the things I know about.

I don't actually care if you use it, I just think the devs are not quite with it all the time so I won't use it. But I use arch anyway so that wouldn't make sense anyway.