For a few months, I filled up with nothing but vpower. Cue fuel shortages and I was forced as with the OP to put normal diesel in. If I'm honest, I don't really notice any difference in performance and now I'm getting 39.7 indicated over 3 tanks compared to 37.something.
That said, in my E46, VPower made the car run significantly smoother and also returned about 3mpg more. Just don't notice that on the E91.
MY14 Space Grey F11 530d M-Sport