Is Garry's Mod good?

Gmod is a good game. Many mods, and is funny )))

For me it's a good game if you want to have some fun or if you want to play rp

yup definitely agree with everyone above

If u like modding and sandbox yes, i have 2000 hours of this game

I have 360 hours of playtime, my opinion is not as big as the person above's BUT, gmod is actually very very fun, I do love modding and the sandbox aspect of it

Yes, of course, S&Box is very poor of content for now

excellent sandbox, especially for playing with friends, I myself recommend to play

yes it is and its really cheap too not to mention when it goes on sale

You're asking this in a GMOD forum, so the answer is yes.