I haven't played a whole lot of Dark Souls III. Obviously DS III is better graphically since you can play it at 60 fps on PC at 1080p with an i5 and a GTX 970/R9 290/GTX 1060/RX 480 or better, while on PS4 Bloodborne is 30 fps at 1080p. I didn't get very far in Dark Souls III because I think Fallout 4 came out right when I first started playing it. I enjoyed the beginning of DS III, but I can't say I was blown away by it the way I was Bloodborne. If you don't take me word for it though, ask
redzero who is a huge Souls fan. I think he ranks Bloodborne as the best in the series. I can't remember if he had DS III or DS I as the second best. I do consider Bloodborne one of the seven perfect games I have ever played since I started gaming in the early 1980s. It's hands down the best game I have played since Skyrim six years ago. I'm hoping like the rumors of From Software releasing a Bloodborne 2 are true. I guess we'll find out at E3. Man I hope when PS5 comes out next decade they release a 60 fps remaster like they did for PS4 with The Last of Us, Uncharted 1-3, and God of War III.