You plural is used when you are speaking formally or informally.
You guys (which I consider a Northern United States phrase) is used informally.
In other words, you would not say to your bosses, "You guys need to get with the program." Sometimes you hear a very bad slang, "youse guys"
When you watch American movies, notice whether the people who say this are in the Northern states or Southern states or out west.
We say ya'll in the South which is very improper English. Ya'll come here! See ya'll later.
You come here! See you later!