The first thing it came to my mind when I saw Vividred Blue Operation was
Figure 17, despite being a really different series. After the attack, of course I drew comparisons with a certain gold hammer as well.
I can't really say the fanservice is "excessive", I was actually expecting quite more.
The premise can't really be taken seriously (especially the idea of the Engine itself). I think I can link the experience of this show so far with Symphogear: no "classic" but an enjoyable show. Enough for me, I guess.