Why did you pick that one? (im asking from lack of knowledge, its not a trap :p)
Yes, just SHA1. I used this because it was easily accessible in C# in .NET. It seems pretty quick (in my very limited testing). Since we aren't concerned about collisions (other files generating the same hash), I figured it would work. If there are other things that would work better, I wouldn't mind hearing about them...
You're right, I could compare before copying, but then if the files were
different, it would be reading both
files an extra time. I figured that the main goal was to make sure that the copy McTool did worked properly.