Having played most Tales games but not all of them, Tales of Symphonia will forever have a special place for me. I think it was somehow the magical combination of artstyle, adventure, and character growth that melded together really well. I played others that were "highly rated" (like Tales of Vesperia), but I struggle to really put my finger on what it is about Symphonia that makes everything feel more cohesive.
BUT, I'm excited for Tales of Arise because I still love the Tales series!