I would. If you are new though, you need to plan out which units you want to get.
300 - Dornia who evolves into Anya (Considered to be one of the best princesses by most) http://aigis.gcwiki.info/?%C9%F5%B0%...E9%A5%CB%A5%A2
500 - Time fairy - Reduces deployment cost by 1 (correct me if i am wrong)
150 - Echidna (Bishop - mage/priest hybrid) she is a pretty good hybrid, and i like her art http://aigis.gcwiki.info/?%CE%B5%D6%...AD%A5%C9%A5%CA
70 - Aria (Soldier - like katie)
I would recommend getting the units in that order if you can. Do note that there are 2 parts to the event, so we'll be farming time crystals for 2 weeks.