Two pretty similar scopes.
Like Randy said, slightly wider field of view with 2x7.
Slightly better for longer shot with 3x9.
I have the 3x9, I like it, and I did make a good 20 yard shot with it, so it does work at close range.
Ironically, when the smoke cleared, I realized in my excitement I had not rolled the scope down to 3x, so I made that shot with 9 power. I didn't notice when I was pulling the trigger.
Today at the range I looked at a target at 9x at 20 yards, it was fuzzy.
Not too fuzzy for combat purposes, though.