V3 is probably the best gameplay wise, but yeah like forlorn said the final chapter in general was Suuuuuper weak everything else was top notch.
DR2 has the best characters, good class trials but the worst trial mini games.
DR1 was very meh in almost everything except Kyoko and mastermind's writing.
Very few interesting trials, obvious twists, poor characters but super interesting setting.
I havent finished the 4th one yet, the real structure of the Funhouse confused the heck outta me. I played DR1 and I feel like Goodbye Despair is way better but anytime Hangmans Gambit or Logic Dive shows up I roll my eyes, trial 3 was a nightmare xD