It all depends on how you like your robot asthetics really. No one is wrong with what they like and dislike about the figures. I personally love both but tend to err towards Arcee more for having much better articulation than the brickformer static bot mode of Chromia. Arcee's winding waist has 4 points of articulation but posing can be limited as the points of articulation tend to "pose" the figure to the right and causes balance issues.