A week into the game and having been a part of the Souls phenomenon since the early days of Demons Souls, this is by far my favourite iteration of the formula. I hope that there is more to come for Bloodborne as the mysteries within get unraveled, I can't get enough of it.
It's familiar enough to grasp its systems in a timely fashion, but different enough to distinguish itself from it's predecessors. I love the more aggressive combat system that rewards initiative.
A part of me longs for the diversity of Covenants in Dark Souls. Bloodborne's 3 (currently known/active) covenants are centered around PVP mechanics and one of them makes co-op almost impossible. I like that they create a risk system to public co-op summons, but I don't feel the incentives are there to experiment with covenants unless your looking a for a completionist playthrough.
But ultimately the game hits all the right spots for me. It's oppressive, it's mysterious, it's tough but fair... and I get to flick out my coattails after destroying an invader.