Well I got Vitch but it wasn't easy or cheap. Used all my saved quartz and had to buy a few packs. I found her ascension lines about making me lose everything and then bringing me up from rock bottom a little too poignant. Got about 20000 valkyries on the banner too. Rare prisms for the anni shop, I guess.
GSSR got me summertime Abby (again) bringing her to NP5, probably my most useless 5* NP5 that I have, but whatever. Apparently she's usable in Buster looping, so I guess i'll give her a try in those berserker heavy nodes. I also finally got another copy of Fae Gawain on the GSSR banner which was a win.
Select-a-SSR I finished my NP5 Bradamante, now to wait for her to get a skill buff/strengthening so I can use her more reliably in Quick looping for easy farming content. Dat ass.
I didn't really know much about buster looping with Vitch, so I found this video which gives you a tier list on how to use which servants:
Basically it boils down to:
High Tier (easy to hit NP amounts with only NP Start CE )
- Artoria (saber)
- Cu (caster)
- Emiya (archer)
Mid Tier (requires Atlas Academy MC and MLB Kaleidoscope)
- Mordred (saber)
- Ibuki (saber)
- Tesla
- Ishtar (archer)
- Ereshkigal
- Artoria (lancer)
- Drake
- Avicebron
- Nero (caster)
- Morgan
- Summer BB
- Artoria (ruler)
- SpIshtar (Buster mode)
- Summer Abby
Low Tier (Shenanigans and 3rd NP battery required)
- Artoria Alter (saber)
- Gilgamesh (archer)
- Melusine (Buster mode)
- Semiramis
- Vitch herself
- Arjuna Alter
It looks like the benefits themselves are that buster doesn't care about how many enemies are in a wave (as long as its 3 or less), nor about which type they are as the refund doesn't matter. It's all about battery skills and cooldown reduction. Downside is that there's less of a damage ceiling since it's very restrictive on skill order, composition, mystic code, and CEs.
I'll have to test it out, but I think that Arts looping will probably stay my default unless it's one of those annoying assassin/berserker farm stages or early farm stages where there aren't enough enemies to get a full refund each stage. Still, it's nice to have options and my Drake is gonna murder caster-heavy stages.