the use of "you are"
When speaking to more than one person or in vosotros, i have gone blank on how to say "you guys are great". Is it "Ustedes son increibles" '''
"Ustedes son increíbles" is fine. If you want to use "vosotros" then you can say "Sois increíbles". The use of one or the other option does not depend on the standard you want to use (formal or colloquial), since the original English sentence is colloquial. It depends on regional variations.
Hope it helps
Doris, just a quick note...."vos" (el voseo) doesn't exist in Spain, only in parts of Latin America, primarily Argentina and Uruguay. When you referred to Spain, you were thinking of "vosotros," which is the informal second-person plural and is conjugated differently from "vos", which is the informal second-person singular. Saludos.
That really depends on what region you are saying it. Spaniards and some South Americans would use vos and sos. I'm from Puerto Rico and we use "Ustedes". Ustedes son increíbles.
Or course, this would be the Argentinian variety!
yes, it is fine