Bloodborne, easily. It feels far more fresh than DS3 does, as well as far more polished (despite frame rate problems). Not having two games' worth of lore strapped to it helps an awful lot here. To me, the world's just far more interesting to me and Yharnam was a joy to explore, especially in the latter half of the game once everything starts to go south. I appreciate there're far fewer ways to build your character than in DS3, and that the multiplayer options are more limited, but I prefer playing faster characters anyway, and never cared for PvP in the other Souls games to start with, so that never really bothered me; the experience is just so focused and refined. I also loved that it returned to the horror elements that were so prevelant in Demon's Souls, and which subsequently got less emphasis as the Dark Souls games went on.
Dark Souls 3 is still a very good game, but it's one where I feel the formula's really starting to get stale. It felt like too much of a retread, like the team were almost at the bottom of the barrel when it came to ideas. It's definitely weighed down by the games before it, and to me it sort of feels as if they were running out of ways to make the game even more challenging to keep up with the demand of the fanbase, lest it get lambasted for being too easy. I'm not a huge fan of the trend of giving every boss multiple phases, but the DLC bosses seem particularly egregious for this, with both Sister Friede and the Demon Princes having three separate health bars. To me, this just made the bosses feel tedious rather than difficult.
I'm a bit burnt out on Souls to be honest, but I still feel a drive to play Bloodborne again, whereas I'm probably fine not touching DS3 for a while.