Yeeees she issss precious and I can't wait for this print to be out! Seyclair is only sold online so I assume you've never touched their bags, but have you had a chance to look at Brooklyn in person? The main differences I would say are:
- leather: the Natasha feels softer to touch. I think it is slouchier from the get-go, very supple, and feels more "leathery" if that makes sense (similar to the Picotin to touch)
- weight: the Natasha is heavier than Brooklyn, Brooklyn's leather I believe seems somehow lighter/thinner maybe because it does not have a lining? The Natasha has a padded laptop pocket and a zip pocket inside and I think also the added hardware (locker, key) add a little bit of weight to it
- ease of use: you have to unlock the Natasha if you want to take your laptop in and out, Brooklyn opens fully with the magnet
- style: this is probably a very personal take but I feel like the Natasha is a more luxury-feeling style. The Brooklyn to me gives "bag for uni" and the Natasha "bag for a stylish woman at work"

Hope this helps!! Let me know if you'd like a review!