Which Summer Servnt Should I Roll For.

Well she's definitely better than Liz, cu is more of a survivability expert and Kiyo is a boss killer meant to melt bosses with all her buster boost and defense down. Tama is definitely better with 175% more attack against males based on overcharge 3 (chaining NP) while Orion's is only 100% and is based on skill level which is hard to get due to tons of mats. Honestly Orion's just good on an arts crit team nothing else and falls from Eury (having 200% more damage to males based on NP level pretty easy as she's a 3 star) on fighting males, yup you heard that right when fighting male sabers Euryale is better than Orion. Rider mordred is an arts rider that could spam meaning she's a good farmer, and ruler Martha is the only full offensive ruler. Dunno your roster so...couldn't really comment on what you should get

Forget about any 4* Lancer. If you have Cu max level and skills, you don't need any 3 and 4 star servants, I even recommend you to grail cu.

As for 5*, there is nothing special in this year other than Merlin and Jalter. Of course, stat-wise any 5* is more than enough to handle all future enemies in this game. So, my tips is to only pull on your favorite 5*.

Ruler Martha? Hell yes, in fact she is the only unique servant (imo) in this summer. I am gonna get her later in 2nd banner. The other ones are just girls in bikini that tease you to spend your SQ or fap while you play (especially Lancer Kiyohime lines...)