Not Miku!She is the Black Rock Shooter!
I went into the OVA assuming that the Black Rock Shooter was an alternate 
version of Miku, but soon enough I knew I was wrong. The artwork was obviously very similar to the personified synthetic music that we all know are Vocaloids (which is not an anime, for crying out loud!). When I first learned about Black Rock Shooter, I assumed the Vocaloid creators were just milking the franchise. Now I’m sure they are, but they also had done it very well.
I used to like the Vocaloids when they first started spreading, with songs like “Romeo and Cinderella” or “Cendrillon” or “Ilevan Polkka”. I liked the robotic sound to them, and I thought it was pretty interesting about the idea of synthetic vocals (not to be mistaken for autotune). Plus I liked the character designs and the different outfits for each song. Slowly, the fanbase started eating away at my interest and I didn’t care much for the Vocaloid franchise, and it almost started to disgust me. I put off BRS for quite some time for that very reason; I thought it was all hype but nothing to back it up aside from the character designs. Well I take that back; I enjoyed the OVA and the TV anime was great.
The two aren’t really related; there are some basic things that are consistent between the two such as the characters and overall theme, but otherwise, I don’t know what the anime will throw at us. It certainly made me cringe at a few points… But at least BRS can take a beating; she’s 
going to need to be strong. The stories are somewhat relatable to most of us (at least to a teenage girl). The two main characters ( in both the OVA and series) are high school girls who struggle with their friendship; The character Black Rock Shooter, is essentially in a personified world where the girl’s are “battling their demons” hence the horns and dark themed…everything. The idea of these demons runs throughout the entire OVA but it is a tad bit tricky to pick up on if you aren’t big on symbolism–although I was watching it bits at a time due to a lack of an attention span and cosplay, so it was hard to piece things together.
Nothing really stood out to me other than the character designs and theme, obviously. The music was pretty average; surprisingly only the opening was
“sung” by Miku, but if you do your research, you would have learned Supercell had writen a song about BRS after the concept art was tossed out into the internet and they used Miku to sing it later on. In the OVA, there is an absence of background music, but it adds to the idea that it’s supposed to come off as relatable and adds to guessing what might happen next (although it’s a bit predictable). The anime brings in more to draw you in, but sometimes it’s over the top…
So my two shots as of now: The story is interesting and somewhat relatable –it drew me in fairly quickly–, I like the concept and the artwork as it’s nicely detailed in the BRS world, and this is something I will definitely follow along to see how it develops. I’m not going to give a rating as the TV spot is only 3 episodes in, but I would say give it a shot.