There seems to be debate on Out for Blood and whether it is worth the hefty investment, so I figured I'd chime in on my experience so far.
I find Mah is far more relevant in my games where I take Out for Blood. While expensive, it gives me that extra oomph needed for the alpha-strike turn. So often, without it, you can't turn on Bane of Kneecaps, which loses you a precious 2" and 1 Ml. Also, with two charges on that key turn, you not only get the extra attacks, but you can do some awesome positioning shenanigans that let you really exploit your triggers. I find I can much more reliably end her leaping spree back in safety, having shoved my enemy into Frank's waiting arms (and am also now back in companion range).
It's one of those things where, yeah, you pay a lot more for what seems like a single AP than most masters would, but in practice, I find it has far more impact than just that. It makes the alpha-strike possible, where without it, I find Mah's activations to be mostly irrelevant because I can't finish anything off, or I can't quite chain to Frank, or I can't quite reach.
Anyhow, my .02. Combined with the FAQ that lets her push herself, I think Mah is relevant, rather than just worse than Ophelia.