OBS any good?

[Indy22]

Hey everyone, im new. Just have a question. I heard OBS can also record your desktop, games and online streams. Has anyone ever used this program? Does it work well? Its apparently free.

Also I'm curious, if you record online streams(you have to watch whatever it is in its entirety) from say Hulu, Netflix, WWEnetwork, etc etc, is there any way for them to actually tell you are doing this? like the screen(and audio) is recorded not downloaded by a download manager like IDM or flashgot. Sorry if this has been answered somewhere else on the forum..