New year event comes notably with the release of New Year Yui. Honorable mention goes to Rei New Year Rei.
New Year Rei is a magic tank like Kuuka but Taunt more often. If you are planning on utilizing her, at least get her 4*. Free units always have inferior stat and they rely heavily on ascend.
Q: Is New Year Rei a great unit?
A: Yes. That quick-to-pull Taunt will solve your problem against Tamaki & Halloween Miyako.
Q: Are you planning on raising her? if yes, to what extent?
A: Yes, at least 4* but i really wanted her to 5*. Thus far, im doing the 6x daily refresh. My jewel stash is kinda getting low and i can't afford to lose not getting some limited unit.