I actually like Callandra, haven't heard of it. Brooklyn is more common. They're both nice names!
I absolutely LOVE the name Brooklyn!! I was gonna name my baby girl Brooke but it didn't go with her 1st name lol. So I like the 2nd one (:
Personally I like the second one. It's adorable. But you are the one going to be calling this baby's name for the rest of your life, so go w what YOU like best!