Musashi

How much money/saved sq do you have to collect all those 5*servants with? All good choices, but not much time between to regain sq after merlin.

I have Okita, and I can tell you right now that she is a very good ST Saber that you would not be disappointed with and I would highly recommend getting her if you can. She can spew ungodly amounts of crit stars with her Q cards, charge her NP quickly, and her NP is pretty dang powerful, even at only lv1. She is a very independent servant and, in my opinion, she is hands down the best Saber in the game right now. As for her vs Musashi, everything I say is based on hearsay as I don't play JP, so take it with a grain of salt. By themselves, Okita is better than Musashi, but if you have Merlin, then Musashi is better than Okita.