A green card does not make ANY difference, and I am 100% sure.
Only Indians and I don't know why they say that it does make a difference.
I know some schools require a green card, like UIC, but anywhere else it does make any difference. I asked and asked and asked about it.
It makes paying the money after the acceptance easier but does not interfere with the decision.
And to prove it. go to any school let's take BU for example and ask them how many students from the 75 people accepted last year have green cards, I bet less than 20%, because of the fact that 50 of the 75 are Indians and very small portion of Indians have green card or citizenship.
Again, I am a green card holder and I wish it makes some difference, I got rejected from 8 schools in the past 2 years. lol, good luck to all of us.