LogFAQs > #986409715

Abyss is my personal favorite but is divisive. Berseria is probably the safe pick for best. Graces f and Xillia 2 have godlike gameplay/battle systems but Graces f's story is kinda whatever/lol and Xillia 2... it's a sequel so you want Xillia 1 under your belt and Xillia 1 is just... it's fine. it's like generic tales game.

tl;dr: Abyss or Berseria

Edit: Other Tales games I've played.

Symphonia: I feel like I go back and forth on if/how much I like it, but I think it holds up... fine.
Symphonia 2: I think I'm kinder on it than most but the mind-boggling gameplay decisions (monster raising, character control) hold it back a lot
Vesperia: Haven't played in forever (since the 360 version near release) but it's in the same league as Vesperia IMO.
Zestiria: Not good. Has Edna tho. And some good music with the Go Shiina composed tracks.
Arise: Okay-ish in the first half. Completely loses itself in the second half, combat gets aggravating here too.