I would consider picking the pup with the best personality... you're gonna fall in love no matter what! But if the pups personality doesn't mesh with your's- then it may not be the "match made in heaven" you're hoping for...
Then again, the one that doesn't seem as outgoing might just need a little time to warm up to you...
I guess I didn't help much....
But congratulations on your new baby- which ever one you choose!