What I hear from people who use it professionally is that it's constantly having features get deprecated, sometimes before they have a full replacement, that it

What I hear from people who use it professionally is that it's constantly having features get deprecated, sometimes before they have a full replacement, that it constantly crashes and has various undocumented SDK behaviors (which sometimes change without warning), etc Over the last five years it went from "not a professional game engine" to "a professional game engine". That doesn't mean it's a good one.