My father in law served in WWII, my father in Korea, both men spoke highly of the SA. When they would come off the front lines the SA gave them coffee and donuts free of charge. The Red Cross either refused to serve enlisted men or made them sigh IOU's if they didn't have money.
You are free to do as you wish with your money, but I personally feel this is the most worthwhile charity.
I had uncles in WWII and I heard the same about the Red Cross charging and the Salvation Army giving for free.
They are a good organization and have very small administrative costs because they aren’t in it for the money.