What is the breeder's take on the two pups? Personally, all other thing being equal, I'd go with F2. I have enough bossy girls around here
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Seriously, it's kind of hard to say without seeing the pups. What are your plans for the pup? Do you have an experienced outsider that could go with you to evaluate pups? If you're planning on competing in some way, then I'd get the advice of your trainer if at all possible.