To whomever this subject applies to, the biased part of me would advise you to pick up Christie as a main, and Mila as someone to know well enough to play in tag. For a character that is so-called "boring", she has some exciting potential when paired with Christie. And now I have further incentive to like the character because she knows how to wear a trenchcoat, which makes her even more exciting to play IMO (now all I need is Christie's trenchcoat back). Additionally, it inspired me to make yuri fanfiction about those two on my spare time.
The unbiased part of me would advise you to find a delicate balance between liking the character for the character and whether the character is easy for you to understand after prolonged play against real opponents. Of course, learn at your own pace.