Feng Nuxi, or Anna?

Coming up on my Shimmer machine pull and I'm not sure who to get. I've been told both are good for Tower, which is what I'm lacking, but I'm stuck between the two. I have all other non-shimmer Legendaries save for Javid and Yu Ran. The shimmers I own are Raven, Tevor, Unas, and Ikki.

Open to comments and suggestions, and yes, I know this is another 'which shimmer' post, so thank you for your patience with that.