Usually the B grades have slight (when I say slight, I mean slight) issues. Like tiny bubbles that formed while casting.
I don't have one, but many in my garrison do and without looking really close at it you won't see any issues. I really recommend it though. I have a Hyperfirm DLT and it is great. My resin E-11, though really accurate, has the potential to break a lot easier than the Hyperfirm, which if dropped will just bounce.
I'll try to find a photo for you, or you could just ask Lewis (slavefire) for a pic.