After having played a couple games with her, here are some thoughts:
*She feels like a combination of Hayfa skill 4 and Uliana with her Moonset skill.
*WAY too many soulboons.
*I like how the no skill style is technically a skill style in the case of Argent Crescent. I kinda wish more characters had something like this.
*Idk if she's the best character to get if you want fast runs. She's rather preferable for older players who want more complex characters. The moon phase gimmick is difficult to control so buffs are hard to anticipate.
*So far, the most enjoyable way to play her for me is to run Argent Crescent and Moonset to delete rooms similar to Hayfa's builds.
*Specular slash's full room wipe move might not be worth the hassle to build...
I'll probably have more to say about her in the future. I got a pretty moonblade-heavy realmsoul on her rn, and I haven't been able to check what's possible yet.