If I enjoy Bloodborne, I'll definitely get it. But as Bloodborne is for free, I'll first want to play that a little bit (not the whole game) before spending 80€ on a game which I might not enjoy.My advice as someone who enjoys those games without being a rabid fan: play Demon's Souls, if you like it then play Dark Souls, and if you still want more, Bloodborne.
From the podcast I know that you, Walter and Griffith enjoy the Souls games a lot, as it's part of almost every second show after the Berserk part I think those games are either hit or miss whether you like them or not, that's why I'm a bit cautious